Urban Area Criteria for the 2010 Census, 53030-53043 [2011-21647]

Agencies

• DEPARTMENT OF COMMERCE
• Bureau of the Census
• Census Bureau

[Federal Register Volume 76, Number 164 (Wednesday, August 24, 2011)]
[Notices]
[Pages 53030-53043]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-21647]



[[Page 53029]]

Vol. 76

Wednesday,

No. 164

August 24, 2011

Part II





Department of Commerce





-----------------------------------------------------------------------





Census Bureau





-----------------------------------------------------------------------





Urban Area Criteria for the 2010 Census; Notice

Federal Register / Vol. 76, No. 164 / Wednesday, August 24, 2011 / 
Notices

[[Page 53030]]


-----------------------------------------------------------------------

DEPARTMENT OF COMMERCE

Bureau of the Census

[Docket Number 110714393-1393-01]


Urban Area Criteria for the 2010 Census

AGENCY: Bureau of the Census, Department of Commerce.

ACTION: Notice of final program criteria.

-----------------------------------------------------------------------

SUMMARY: This notice announces the Bureau of the Census' (hereafter, 
Census Bureau's) final criteria for defining urban areas based on the 
results of the 2010 Decennial Census (the term ``urban area'' as used 
throughout this notice refers generically to urbanized areas of 50,000 
or more population and urban clusters of at least 2,500 and less than 
50,000 population). This notice also provides a summary of comments 
received in response to proposed criteria published in the August 24, 
2010, Federal Register (75 FR 52174), as well as the Census Bureau's 
response to those comments.
    The Census Bureau's urban-rural classification is fundamentally a 
delineation of geographic areas, identifying both individual urban 
areas and the rural areas of the nation. The Census Bureau's urban 
areas represent densely developed territory, and encompass residential, 
commercial, and other nonresidential urban land uses. The Census Bureau 
delineates urban areas after each decennial census by applying 
specified criteria to decennial census and other data. Since the 1950 
Census, the Census Bureau has reviewed and revised these criteria, as 
necessary, for each decennial census. The revisions over the years 
reflect the Census Bureau's desire to improve the classification of 
urban and rural territory to take advantage of newly available data, as 
well as advancements in geographic information processing technology.

DATES: Effective Date: The Census Bureau will begin implementing the 
criteria as of August 24, 2011.

FOR FURTHER INFORMATION CONTACT: Vincent Osier, Chief, Geographic 
Standards and Criteria Branch, Geography Division, U.S. Census Bureau, 
via e-mail at vincent.osier@census.gov or telephone at (301) 763-3056.

SUPPLEMENTARY INFORMATION: The Census Bureau's delineation of urban 
areas is designed to identify densely developed territory, and 
encompass residential, commercial, and other nonresidential urban land 
uses. The boundaries of this ``urban footprint'' have been defined 
using measures based primarily on population counts and residential 
population density, but also through criteria that account for 
nonresidential urban land uses, such as commercial, industrial, 
transportation, and open space that are part of the urban landscape. 
Since the 1950 Census, when densely settled urbanized areas (UAs) of 
50,000 or more people were first defined, the urban area delineation 
process has addressed nonresidential urban land uses through criteria 
designed to account for commercial enclaves, special land uses such as 
airports, and densely developed noncontiguous territory.
    In delineating urban areas and the resultant classification of 
territory outside these urban areas as rural, the Census Bureau does 
not take into account or attempt to meet the requirements of any 
nonstatistical uses of these areas or their associated data. 
Nonetheless, the Census Bureau recognizes that other government 
agencies use the Census Bureau's urban-rural classification for 
allocating program funds, setting program standards, and implementing 
aspects of their programs. The agencies that use the classification and 
data for such nonstatistical purposes should be aware that the changes 
to the urban area criteria might affect the implementation of their 
programs.
    The Census Bureau is not responsible for the use of its urban-rural 
classification in nonstatistical programs. If a federal, tribal, state, 
or local government agency voluntarily uses the urban-rural 
classification in a nonstatistical program, it is that agency's 
responsibility to ensure that the classification is appropriate for 
such use. In considering the appropriateness of the classification for 
use in a nonstatistical program, the Census Bureau urges each 
government agency to consider permitting appropriate modifications of 
the results of implementing the urban-rural classification specifically 
for the purposes of its program. When a program permits such 
modifications, the Census Bureau urges each agency to describe and 
clearly identify the different criteria being applied to avoid 
confusion with the Census Bureau's official urban-rural 
classifications.

I. Summary of Changes Made to the 2010 Census Urban Area Criteria

    The following table compares the final 2010 Census delineation of 
urban areas criteria with the provisions that were proposed in the 
August 24, 2010, Federal Register (75 FR 52174).

------------------------------------------------------------------------
                              Proposed 2010 Census    Final 2010 Census
          Criteria                  criteria              criteria
------------------------------------------------------------------------
Identification of Initial     Census tract and      Census tract and
 Urban Area Cores.             block population      block population
                               density, count, and   density, count, and
                               size thresholds.      size thresholds.
                               Use of National       Use of National
                               Land Cover Database   Land Cover Database
                               to identify           to identify
                               territory with a      territory with a
                               high degree of        high degree of
                               impervious land       impervious land
                               cover.                cover.
Inclusion of Noncontiguous    Bodies of water and   Bodies of Water.
 Territory Separated by        wetlands as
 Exempted Territory.           identified in the
                               National Land Cover
                               Database.
Inclusion of Noncontiguous    Maximum hop distance  Maximum hop distance
 Territory via Hops and        0.5 miles, maximum    0.5 miles, maximum
 Jumps.                        jump distance 2.5     jump distance 2.5
                               miles, and no hops    miles, and no hops
                               after jumps.          after jumps.
                               Solicited comment
                               on returning to the
                               maximum jump
                               distance of 1.5
                               miles implemented
                               for pre-Census 2000
                               delineations.
Inclusion of Enclaves.......  Two types of          Two types of
                               enclaves are          enclaves are
                               identified when       identified when
                               surrounded solely     surrounded solely
                               by qualifying land    by qualifying land
                               territory, and one    territory, and one
                               type of enclave can   type of enclave can
                               be included when      be included when
                               surrounded by both    surrounded by both
                               land that qualified   land that qualified
                               for inclusion in      for inclusion in
                               the urban area and    the urban area and
                               water.                water.

[[Page 53031]]

 
Splitting Large Urban         The urban             The agglomeration
 Agglomerations.               agglomeration         consists of
                               encompasses at        urbanized areas
                               least 1,000,000       defined separately
                               people. Split         for Census 2000.
                               occurs at the         Split location is
                               metropolitan          guided by location
                               statistical area      of Census 2000
                               boundary (or          urbanized area
                               metropolitan New      boundaries.
                               England city and      Potential split
                               town area), and       locations will also
                               compensates for       consider
                               incorporated place    metropolitan
                               and census            statistical area,
                               designated place      county, place, and/
                               boundaries to         or minor civil
                               attempt to avoid      division boundaries
                               splitting places      as well as distance
                               between urban areas.  from each component
                                                     urbanized area.
Merging Individual Urban      N/A.................  Merge qualifying
 Areas.                                              territory from
                                                     separately defined
                                                     2010 Census urban
                                                     cores that share
                                                     territory contained
                                                     within the
                                                     boundaries of the
                                                     same Census 2000
                                                     urban area. Merge
                                                     only occurs if an
                                                     area is at risk of
                                                     losing urbanized
                                                     area or urban
                                                     status and is
                                                     preventable by the
                                                     merge.
Inclusion of Indentations...  5 square mile         3.5 square mile
                               maximum area of the   maximum area of the
                               territory within      territory within
                               the indentation to    the indentation to
                               be added to the       be added to the
                               urban area.           urban area.
Inclusion of Airports.......  Annual enplanement    Currently
                               of at least 2,500     functioning airport
                               passengers and be     with an annual
                               contiguous to the     enplanement of at
                               urban area.           least 2,500
                                                     passengers and is
                                                     within 0.5 miles to
                                                     the urban area.
Additional Nonresidential     N/A.................  Inclusion of groups
 Urban Territory.                                    of census blocks
                                                     with a high degree
                                                     of impervious
                                                     surface and are
                                                     within 0.25 miles
                                                     of an urban area.
Assigning Urban Area Titles.  Clear, unambiguous    Clear, unambiguous
                               title based on        title based on
                               commonly recognized   commonly recognized
                               place names derived   place names derived
                               from incorporated     from incorporated
                               places, census        places, census
                               designated places,    designated places,
                               minor civil           minor civil
                               divisions, and the    divisions, and the
                               Geographic Names      Geographic Names
                               Information System.   Information System.
Minimum Population Residing   At least 1,500        At least 1,500
 Outside Institutional Group   persons must reside   persons must reside
 Quarters.                     outside               outside
                               institutional group   institutional group
                               quarters for the      quarters for the
                               area to qualify as    area to qualify as
                               its own urban area.   its own urban area.
Density Criteria for          Census blocks on      N/A.
 Military Installations.       military
                               installations with
                               2,500 or more
                               persons are
                               automatically given
                               a population
                               density of 1,000
                               persons per square
                               mile; census blocks
                               between 1,000 and
                               2,500 population
                               are automatically
                               given a population
                               density of 500
                               persons per square
                               mile.
------------------------------------------------------------------------

Throughout this Federal Register Notice and the urban area criteria for 
the 2010 Census, the Census Bureau uses the term ``contiguous'' where 
the term ``adjacent'' was used in the proposed 2010 urban area 
criteria.

II. History

    Over the course of more than a century of defining urban areas, the 
Census Bureau has introduced conceptual and methodological changes to 
ensure that the urban-rural classification keeps pace with changes in 
settlement patterns and with changes in theoretical and practical 
approaches to interpreting and understanding the definition of urban 
areas. Prior to the 1950 Census, the Census Bureau primarily defined 
``urban'' as any population, housing, and territory located within 
incorporated places with a population of 2,500 or more, but with the 
additional allowances to classify certain New England towns and other 
areas urban by ``special rule''. That definition was easy and 
straightforward to implement, requiring no need to calculate population 
density, to understand and account for actual settlement patterns on 
the ground in relation to boundaries of administrative units, or to 
consider densely settled populations existing outside incorporated 
municipalities. For much of the first half of the twentieth century, 
that definition was adequate for defining ``urban'' and ``rural'' in 
the United States, but by 1950 it became clear that it was incomplete.
    Increasing suburbanization, particularly outside the boundaries of 
large incorporated places led the Census Bureau to adopt the Urbanized 
Area (UA) concept for the 1950 Census. At that time, the Census Bureau 
formally recognized that densely settled communities outside the 
boundaries of large incorporated municipalities were just as ``urban'' 
as the densely settled population inside those boundaries and the large 
unsettled or sparsely settled areas inside those boundaries were just 
as ``rural'' as those outside. Due to the limitations in technology for 
calculating and mapping population density, delineation of UAs was 
limited to cities of at least 50,000 people (in the 1940 Census) and 
their surrounding territory. The geographic units used to analyze 
settlement patterns were enumeration districts (similar to census block 
groups), but to facilitate and ease the delineation process, each 
incorporated place was analyzed as a single unit--that is, the overall 
density of the place was calculated and if it met the minimum 
threshold, it was included in its entirety in the UA. Outside UAs, 
``urban'' was still defined as any place with a population of at least 
2,500. The Census Bureau recognized the need to identify distinct 
unincorporated communities existing outside the UAs, and thus created 
the ``census designated place'' (CDP) \1\ and designated those with 
populations of at least 2,500 as urban.
---------------------------------------------------------------------------

    \1\ A CDP is a statistical geographic entity encompassing a 
concentration of population, housing, and commercial structures that 
is clearly identifiable by a single name, but is not within an 
incorporated place. CDPs are the statistical geography counterparts 
of incorporated places.
---------------------------------------------------------------------------

    Starting with the 1960 Census and continuing through the 1990 
Census, the Census Bureau made a number of changes to the methodology 
and criteria for defining UAs, but retained the 1950 Census basic 
definition of ``urban'' which was defined as UAs with a population of 
50,000 or more and defined primarily on the basis of population 
density, as well as places with a population of 2,500 or more located 
outside UAs. The enhancements made by the Census Bureau to the 
methodology and criteria used during this period included:

[[Page 53032]]

    (1) Lowering, and eventual elimination, of minimum population 
criteria for places that formed the ``starting point'' for delineating 
a UA. This made recognition of population concentrations independent of 
the size of any single place within the concentration.
    (2) Identification of ``extended cities''--incorporated places 
containing substantial amounts of territory with very low population 
density, which were divided into urban and rural components using 100 
persons per square mile (ppsm) as the density criterion. This kept the 
extent of urban territory from being artificially exaggerated by 
sparsely settled and overbounded incorporated places.
    (3) Implementation for the 1990 Census of nationwide coverage by 
census blocks, and use of interactive analysis of population density 
patterns at the census block level, or by groups of blocks known as 
``analysis units,'' using Census Bureau-developed delineation software. 
This enhancement allowed greater flexibility when analyzing and 
defining potential UAs, as opposed to using enumeration districts and 
other measurement units defined prior to decennial census data 
tabulation.
    (4) Implementation of qualification criteria for incorporated 
places and CDPs for inclusion within a UA based on the existence of a 
densely populated ``core'' containing at least fifty percent of the 
place's population. This eliminated certain places from the urban area 
classification because much of their population was scattered rather 
than concentrated.
    For the 2000 Census (Census 2000), the Census Bureau took advantage 
of technological advances associated with geographic information 
systems (GIS) and spatial data processing to classify urban and rural 
territory on a more consistent and nationally uniform basis than had 
been possible previously. Rather than delineating urban areas in an 
interactive and manual fashion, the Census Bureau developed and 
utilized software that automated the examination of population 
densities and other aspects of the criteria. This new automated urban 
area delineation methodology provided for a more objective application 
of criteria compared to previous censuses in which individual 
geographers applied the urban area criteria to delineate urban areas 
interactively. This new automated approach also established a baseline 
for future delineations to enable the Census Bureau to provide 
comparable data for subsequent decades.

Changes for Census 2000

    The Census Bureau adopted six substantial changes to its urban area 
criteria for Census 2000:
    (1) Defining urban clusters. Beginning with Census 2000, the Census 
Bureau created and implemented the concept of an urban cluster. Urban 
clusters (UCs) are defined as areas of at least 2,500 and less than 
50,000 persons using the same residential population density-based 
criteria as applied to UAs. This change provided for a conceptually 
consistent, seamless classification of urban territory. For previous 
censuses, the lack of a density-based approach for defining urban areas 
of less than 50,000 persons resulted in underbounding of urban areas 
where densely settled populations existed outside place boundaries or 
overbounding when cities included territory with low population 
density. Areas where annexation had lagged behind expansion of densely 
settled territory, or where communities of 2,500 up to 50,000 people 
were not incorporated and were not defined as CDPs, were most affected 
by the adoption of density-based UCs. As a result of this change, the 
Census Bureau no longer needed to identify urban places located outside 
UAs for the purpose of its urban-rural classification.
    (2) Disregarding incorporated place and CDP boundaries when 
defining UAs and UCs. Taking place boundaries into account in previous 
decades resulted in the inclusion of territory with low population 
density within UAs when the place as a whole met minimum population 
density requirements, and excluded densely settled population when the 
place as a whole fell below minimum density requirements. 
Implementation of this change meant that territory with low population 
density located inside place boundaries (perhaps due to annexation, or 
the way in which a CDP was defined) no longer necessarily qualified for 
inclusion in an urban area. However, it also meant that nonresidential 
urban land uses located inside a place's boundary and located on the 
edge of an urban area might not necessarily qualify to be included in a 
UA or UC.
    (3) Adoption of 500 persons per square mile (ppsm) as the density 
criterion for recognizing some types of urban territory. The Census 
Bureau adopted a 500 ppsm population density threshold at the same time 
that it adopted its automated urban area delineation methodology. This 
ensured that census blocks that might contain a mix of residential and 
nonresidential urban uses, but might not have a population density of 
at least 1,000 ppsm, could qualify for inclusion in an urban area. For 
the 1990 Census, geographers could interactively modify analysis units 
to include census blocks with low population density that might contain 
nonresidential urban uses, while still achieving an overall population 
density of at least 1,000 ppsm. Adoption of the lower density threshold 
facilitated use of the automated urban area delineation methodology, 
and provided for comparability with the 1990 methodology. This change 
did not result in substantial increases to the extent of urban areas.
    (4) Increase in the jump distance from 1.5 to 2.5 miles. The Census 
Bureau increased the jump distance from 1.5 to 2.5 miles. A ``jump'' is 
the distance across territory with low population density separating 
noncontiguous qualifying territory (area of high population density) 
from the main body of an urban area. The increase in the jump distance 
was a result of changing planning practices that led to the creation of 
larger clusters of single-use development. In addition, research 
conducted prior to Census 2000 showed that some jumps incorporated in 
UA definitions in 1990 were actually longer than 1.5 miles as a result 
of the subjective identification of the gap in developed territory. As 
used in previous censuses, only one jump was permitted along any given 
road connection.
    (5) Introduction of the hop concept to provide an objective basis 
for recognizing small gaps within qualifying urban territory. For 
Census 2000, the Census Bureau officially recognized the term ``hops,'' 
which is defined as gaps of 0.5 mile or less between qualifying urban 
territory. Hops are used primarily to account for territory in which 
planning and zoning processes resulted in alternating patterns of 
residential and nonresidential development over relatively short 
distances. This provided for a more consistent treatment of short gaps 
with low population density, some of which had been treated as jumps in 
the 1990 urban area delineation process (and not permitted if 
identified as a second jump), while others were interpreted as part of 
the pattern of urban development and grouped with contiguous, higher 
density blocks to form qualifying analysis units.
    (6) Adoption of a zero-based approach to defining urban areas. The 
urban area delineation process in previous censuses had generally been 
an additive process, where the boundary of a UA from the previous 
census provided the starting point for review for the next census. The 
changes made for Census 2000 were substantial enough to warrant

[[Page 53033]]

the Census Bureau to re-evaluate the delineation of all urban areas as 
if for the first time, rather than simply making adjustments to the 
existing boundary. The Census Bureau adopted this zero-based approach 
to ensure that all urban areas were nationally defined in a consistent 
manner.
    The six changes described above represent the major modifications 
implemented for Census 2000. They illustrate a substantial shift in 
approach adopted by the Census Bureau in its procedure for delineating 
urban areas. The availability of new datasets and continued research 
since Census 2000 showed the potential for further improvements for the 
2010 Census.

III. Summary of Comments Received in Response to Proposed Criteria

    The notice published in the August 24, 2010 Federal Register (75 FR 
52174) and requested comments on proposed criteria for the 2010 Census 
urban areas. In response, the Census Bureau received 179 comment 
letters from regional planning and nongovernmental organizations, 
municipal and county officials, Members of Congress, state governments, 
federal agencies, and individuals.
Comments Pertaining to Proposed Criteria for Splitting Large Urban 
Agglomerations
    The proposed criteria for splitting large agglomerations formed 
during the delineation process drew the largest number of comments. Of 
the 179 responses received, 160 commented on the proposed criteria for 
splitting large agglomerations. Of these, 102 commenters expressed 
concern about the potential merger of specific pairs of urban areas, 
with 87 commenters expressing concern about the impact on planning and 
policymaking as well as the potential loss of federal funding as a 
result of the loss of individual UA status. Other commenters expressed 
concern about the loss of local control over funding allocation and 
policy decisions, lack of consistency with the Census 2000 urban 
classification, and loss of meaningful data.
    Twenty-five commenters supported splitting large urban 
agglomerations along metropolitan statistical area boundaries or (in 
New England) New England city and town area (NECTA) boundaries. Ten 
also supported the proposal to avoid splitting incorporated places and 
CDPs between urban areas. Six of the comments suggested splitting urban 
areas along NECTA Division in New England where available or Primary 
Metropolitan Statistical Area boundaries (although the latter are no 
longer defined by the Office of Management and Budget). Thirteen 
commenters specifically suggested basing the urban agglomeration splits 
on the location of the current urban area boundaries; those commenters 
who expressed favor for maintaining separate UA status for areas 
identified as part of potential agglomerations can be assumed to favor 
splitting along Census 2000 UA boundaries. Five commenters advocated 
the use of commuting data to determine how and where to split large 
agglomerations. Twenty-six commenters favored splitting urban 
agglomerations within metropolitan statistical areas, with some 
wondering whether the lack of such a provision in the proposed criteria 
was an oversight.
    The Census Bureau received sixty-five comments regarding the 
minimum population threshold to identify which urban agglomerations 
should be split. Of these, six commenters favored the proposed 
1,000,000 person threshold. Thirty commenters favored a 250,000 person 
threshold and eleven commenters suggested keeping the 50,000 person 
threshold implemented for the Census 2000 delineation. Among other 
suggested minimum population thresholds, commenters also suggested 
using a threshold consistent with Federal Transit Administration and 
Federal Highway Administration funding thresholds, or no minimum 
population threshold at all.
    In addition to requests for clarification, the Census Bureau also 
received comments expressing concern about the arbitrary nature of the 
proposed criteria for splitting and merging urban areas as well as a 
lack of local input. Other suggestions include the identification of 
combined urban areas through commuting patterns, examining each urban 
agglomeration individually to determine the location of each split 
boundary, defining agglomeration splits along county and sub-county 
boundaries, and retaining the current split boundaries defined for the 
Census 2000 delineation.
    In response to the comments regarding criteria for splitting large 
agglomerations, the Census Bureau will adopt criteria ensuring that 
urbanized areas defined for Census 2000 continue to be identified as 
separate urbanized areas for the 2010 Census, but only if these areas 
continue to qualify as urbanized under the 2010 urban area delineation 
criteria. The boundary used to split large agglomerations will be based 
on the locations of Census 2000 urban area boundaries. To the extent 
possible, this will facilitate continuity and comparability between the 
Census 2000 and the 2010 Census urban area definitions.
Comments Pertaining to Proposed Hop and Jump Criteria
    The Census Bureau received seventy-five comments regarding the 
proposed hop and jump criteria designed to include noncontiguous, but 
qualifying territory within an urban area. Of these, forty commenters 
suggested lowering the maximum jump distance threshold from 2.5 to 1.5 
miles. These commenters suggested that, in addition to preventing the 
consolidation of functionally separate urban areas, a shorter maximum 
jump distance would improve the overall delineation by preventing 
inclusion in the urban area of long stretches of qualifying territory 
that are more appropriately classified as rural, especially with the 
presence of large expanses of exempted territory and long distance 
commuting patterns. Further, one commenter expressed concern that 
retaining the existing 2.5-mile maximum jump threshold indicates that 
the Census Bureau has moved away from a morphological concept of urban 
towards one based on function relationships.
    Thirty-three commenters favored no change to the 2.5 mile maximum 
jump distance threshold. Reasons for retention of the 2.5 mile maximum 
jump distance provided by these commenters included retaining 
consistency with the Census 2000 urban area delineation, the ability to 
account for future urbanization and extended suburbanization, and 
mitigation of the presence of undevelopable land not identified by the 
Census Bureau. One commenter suggested that the 2.5 maximum jump 
distance allowed is too restrictive in coastal areas where large areas 
of wetlands are present, even if such territory is identified as 
exempted. One commenter suggested different maximum jump thresholds 
should be applied to urban areas of different population sizes, with 
longer jumps allowed for larger initial urban cores.
    Three commenters expressed concern that the proposed criteria do 
not allow for a second iteration of hops after jumps; one commenter 
agreed with the proposal to not allow hops after a jump had been made. 
Two commenters requested clarification on the sequence of hops and 
jumps in relation to the identification of airports, wondering whether 
it is possible to hop or jump from an urban area to additional 
qualifying territory if airports are included in the urban area after 
the hop and jump criteria have been implemented. One commenter 
suggested that all intervening census

[[Page 53034]]

blocks separating an initial urban core and its noncontiguous 
qualifying territory must have a minimum population density of at least 
500 ppsm. One commenter suggested not allowing multiple hops, and 
another opposed including any noncontiguous densely settled territory 
via hops and jumps.
    Based on the comments received as well as a general desire to 
maintain comparability between the Census 2000 and 2010 Census 
criteria, the Census Bureau will continue to use the maximum jump 
distance of 2.5 miles, as well as the maximum hop distance of 0.5 
miles. The Census Bureau notes that the comments pertaining to the 
maximum distance of a jump did not strongly favor either retention of 
the 2.5-mile maximum jump distance implemented for the Census 2000 or 
reversion to the 1.5 mile maximum of previous decades. In response to 
concerns that application of the hop and jump criteria allows urban 
areas to reach too far into rural territory, the Census Bureau will not 
allow for a second iteration of hops after a jump. The Census Bureau 
will also retain the proposed requirement for an overall density of at 
least 500 ppsm for all noncontiguous qualifying territory (both the 
high density destination and intervening territory).
Comments Pertaining to Proposed Criteria for Identifying and Linking 
Across Exempted Territory
    The Census Bureau received thirty-three comments pertaining to the 
proposed criteria for recognizing territory in which urban development 
is constrained due to either topographic or land cover/land use 
conditions during the inclusion of noncontiguous, but qualifying urban 
territory. Sixteen commenters agreed with the proposed criteria to 
identify wetlands as exempted territory in addition to water features, 
national parks, and national monuments as was done for the Census 2000 
delineation. Five of these commenters, however, suggested that wetlands 
only be identified as exempt if the maximum jump distance was lowered 
to 1.5 miles. In addition to identifying wetlands as exempted 
territory, five commenters suggested additional classes of land cover 
restricting development, such as farmland, forested land, conservation 
easement properties, and steeply sloped territory in which mountain 
passes are present. Although still in agreement with the identification 
of wetlands as exempted territory, commenters expressed additional 
concerns regarding the vintage of the 2001 National Land Cover Database 
(NLCD) developed by the Multi-Resolution Land Characteristics 
Consortium (MRLC) \2\ and suggested using the NLCD 2006 update as well 
as incorporating additional wetlands datasets based on ground-truth 
samples, more current imagery, and/or projection models, and locally 
produced surface data where available. Commenters also expressed 
concern about the objectivity in determining whether these territories 
will not be developed as well as not be included in the overall 
population density calculation of urban areas.
---------------------------------------------------------------------------

    \2\ The NLCD includes data for the entirety of the United 
States, Puerto Rico, and the U.S. Virgin Islands.
---------------------------------------------------------------------------

    Five commenters opposed the identification of wetlands as exempted 
territory, citing NLCD data vintage and quality, the compatibility of 
the NLCD to data within the Census Bureau's Master Address File/
Topologically Integrated Geographic Encoding and Referencing (MAF/
TIGER) database (MTDB), lack of local input in defining wetlands, and 
the proper vetting of NLCD prior to inclusion in the criteria as issues 
of concern. Commenters also suggested that the combination of wetlands 
and water features as exempted territory with a 2.5-mile maximum jump 
distance threshold exaggerates the amount of urban territory defined 
and noted that only considering wetlands as exempted does not account 
for other types of land cover/uses that act as barriers to urban 
development. One commenter also questioned how close wetlands territory 
must be to road segments as well as why it is necessary to be located 
on both sides of the road, to be considered exempted territory.
    The Census Bureau received three comments opposing the 
identification of water features as exempted territory suggesting that 
wide expanses of water should clearly separate urban areas. One 
commenter suggested the use of Radio Detection And Ranging (RADAR) 
mapping to better identify water landscape features as exempted 
territory. Three commenters opposed the identification of all exempted 
territory in the urban area delineation criteria. These commenters 
suggested that the exempted territory criteria allow for the extension 
of urban areas across county boundaries, which is counter to the 
overall intent for defining urban areas by the Census Bureau. Note that 
the Census Bureau's urban area criteria have always allowed for the 
extension of urban area boundaries across the county boundaries. Other 
commenters suggested adding floodplains, regional parks, national 
wildlife areas, steeply sloped terrain, and other defined open space 
with restricted development properties as exempted territory classes.
    In response to the comments received, the Census Bureau will 
continue to take into account exempted territory when delineating urban 
areas, as it has for several decades. The Census Bureau will also 
continue to only consider conditions where exempted territory is on 
both sides of a road, otherwise development would not be fully 
constrained. However, based on concerns raised by commenters and to 
maintain decennial comparability, for the 2010 Census urban area 
delineation, bodies of water included in the Census Bureau's MTDB will 
be the only specific class of territory identified as exempted. Similar 
to the Census 2000 delineation criteria, additional exempted territory 
will include land area in which the populations of the census blocks on 
both sides of a road segment are zero and the road connection crosses 
at least 1,000 feet of water. This methodology is designed to identify 
unpopulated wetlands and floodplains adjacent to water that separate 
areas of urban development. Nonetheless, the Census Bureau decided to 
break from the Census 2000 delineation criteria by not considering 
national parks and national monuments as exempted territory because of 
concerns regarding the data quality and vintage. The Census Bureau also 
decided not to include any of the proposed wetlands classes in the 
category of exempted territories. The presence of large expanses of 
wetlands territory coupled with a maximum jump distance threshold of 
2.5 miles would facilitate the over extension of urban territory in 
certain locations around the nation. The consideration of wetlands as 
exempted territory imparts a regional bias to the delineation process 
due to the greater prominence of wetlands in some parts of the country, 
such as the southern and southeastern United States. The Census Bureau 
has decided against adding additional classes of exempted territory 
until a larger and more robust category of land cover/land use types 
acting as barriers to urban development can be identified consistently 
and uniformly for the entire United States and Puerto Rico.
Comments Pertaining to Proposed Criteria To Qualify Territory 
Containing a High Degree of Impervious Surface Land Cover
    Twenty-three commenters responded to the proposed use of the NLCD 
to assist in identifying and qualifying as urban, sparsely populated 
urban-related territory associated with a high degree

[[Page 53035]]

of impervious surface land cover. Eighteen comments favored adoption of 
the proposal to qualify territory based on the percentage of impervious 
surfaces. Ten commenters, however, expressed concern about the vintage 
of the data, questioning the relevance of using the 2001 NLCD as it is 
more representative of urban conditions at the time of Census 2000 and 
does not account for subsequent development. Commenters suggested using 
the NLCD 2006 update, supplemental land cover/land use datasets based 
on ground-truth samples, more current imagery, and/or projection 
models, as well as local opinion and locally produced surface data, 
where available. Five commenters who favored using impervious surface 
data conditioned their support on the premise that the maximum jump 
distance threshold should revert to 1.5 miles to prevent the over 
extension of urban territory. Other commenters expressed concern about 
the overall quality of the NLCD, how well these data match data in the 
MTDB, that introduction of these data were not properly vetted, and 
requested that the Census Bureau provide public products merging 
impervious surface data with information for census blocks.
    After considering the comments received, the Census Bureau, as 
described in the proposed criteria, will include impervious surface 
data when delineating urban areas as a means to identify business 
districts, commercial, and industrial zones, located both on the edge 
and in the interior of an urban area that would not qualify as urban 
based on residential population measures alone. In response to the 
comments, the Census Bureau will use the 2006 NLCD update wherever 
available and will use the 2001 NLCD in areas of the Nation not yet 
covered by the 2006 NLCD update in its efforts to promote a more 
publicly replicable urban area delineation. For the 2010 Census urban 
area delineation, the most consistent, comprehensive, and accessible 
impervious surface database for the United States and Puerto Rico is 
the NLCD.
Comments Pertaining to Proposed Use of Census Tracts as Building Blocks
    The Census Bureau received twenty-one comments regarding the 
proposed use of the census tract as the analysis unit (or geographic 
building block) during the delineation of the initial urban area core. 
Of these, sixteen commenters favored the proposal. Three commenters 
also supported the use of census tracts as analysis units, but 
suggested modifications to the initial urban core delineation criteria. 
These commenters expressed concern that the minimum population density 
threshold of 500 ppsm was too high, proposed increasing the maximum 
land area threshold to four square miles, and suggested applying the 
Census 2000 block group-based delineation criteria after using census 
tracts as analysis units to capture lower density territory in 
mountainous areas resulting from census geography primarily being 
defined along visible features. The two letters opposing the use of 
census tracts as analysis units both questioned the relevance of this 
criterion when delineation of initial urban cores also occurs at the 
census block level. An additional concern was about the reduced 
population density measurements resulting from the inclusion of water 
area in census tracts (although population density is based only on 
land area). One letter requested clarification on the iterative nature 
of the initial urban core building process once the delineation 
criteria moves down to the census block level.
    In response to the comments received regarding these criteria, the 
Census Bureau will replace census block groups with census tracts as 
the analysis unit during the delineation of the initial urban area core 
for the 2010 Census urban area delineation as described in the proposed 
criteria. Changing the urban area core delineation analysis unit to the 
census tract offers advantages of increased consistency and 
comparability, since census tracts are more likely to retain their 
boundaries over the decades than census blocks and block groups. The 
Census Bureau decided to retain the minimum 500 ppsm threshold to 
maintain comparability with the Census 2000 urban area delineation. 
This population density threshold was chosen to allow the Census Bureau 
to account for the inclusion of open space and other nonresidential 
urban uses within census tracts and blocks that also contain 
residential development. The Census Bureau also decided not to adopt 
the suggested maximum census tract size criterion of four square miles 
and to include a maximum census tract size criterion of three square 
miles to avoid adding large amounts of sparsely settled territory to 
urban areas. Water area, as depicted in the Census Bureau's MTDB, has 
never been included in population density calculations for the urban 
area delineation program.
    Research by the Census Bureau has indicated that the initial urban 
cores tend to experience slight decreases in territory and only slight 
increases in population qualifying as urban when the initial analysis 
unit is changed from the block group to the census tract. The small 
reduction in initial urban area core territory is due to the use of 
census tracts, which are larger geographic units and therefore less 
likely than block groups to qualify under the density requirements. 
Similar to the way block groups were used for Census 2000, if a census 
tract does not meet specified area measurement and density criteria, 
the focus of analysis will shift to individual census blocks within the 
tract, and delineation will continue at the block level. As a result, 
when using census tracts, the delineation process shifts to census 
block-level analysis sooner than would be the case when using block 
groups. This methodology is iterative as additional qualifying census 
tracts and blocks are added to the initial urban core until no such 
qualifying territory exists during this phase of the delineation.
Comments Pertaining to Proposed Criteria for Inclusion of Enclaves and 
Indentations
    The Census Bureau received six comments regarding proposed criteria 
for inclusion of territory in indentations and enclaves formed during 
the delineation process. Three commenters supported the proposed 
criteria for including indentations, by way of criteria similar to 
those implemented for the Census 2000, citing the jagged nature of the 
current urban area boundaries. Conversely, one commenter opposed the 
indentation criteria if the only purpose was to produce a more 
cartographically pleasing depiction of boundaries. One commenter 
suggested modifying the enclave criteria by lowering the maximum area 
threshold of five square miles and requiring the majority of the 
enclave boundary to border territory qualifying as urban. One commenter 
questioned if these criteria are still necessary.
    In response to the comments received regarding the criteria for the 
inclusion of enclaves and indentations, the Census Bureau decided not 
to make any changes to the proposed enclave and indentation criteria to 
maintain comparability from one decade to another. In situations where 
an enclave is identified and is contiguous to both qualifying territory 
and a water feature, the territory within the enclave can only be 
captured if the line of contiguity with the qualifying territory is 
greater than the line of contiguity with the water feature. These 
criteria are designed to qualify internal and fringe territory that may 
not qualify as urban due to large census blocks with a substantial 
presence of open space (parks, golf

[[Page 53036]]

courses, etc.) but should be considered part of the urban footprint.
Comments Pertaining to Proposed Criteria for Inclusion of Airports
    The Census Bureau received ten comments pertaining to the proposed 
criteria for including airports in urban areas; all ten agreed with the 
proposal to include census blocks in their entirety approximating the 
territory encompassed by major airports. One commenter, however, 
disagreed with the proposal to lower the minimum enplanement threshold 
to 2,500 passengers, noting that commercial hubs are better represented 
than facilities with a mixture of charter or business flights and 
joint-use (military/general aviation) airports according to commercial 
enplanements only. This commenter also suggested that the criteria 
should take into consideration the number of flights. Two commenters 
favored the inclusion of cargo flights in addition to general aviation 
enplanements when identifying airports according to the minimum 
enplanement threshold. Another commenter noted that more recent 
enplanement data (2009) are available through the Federal Aviation 
Administration (FAA) than were referenced in the proposed criteria. 
Additional comments included requests for data content clarification 
such as whether the data include commercial only, military activities, 
or all enplanements, as well as whether the Census Bureau will consider 
cargo weight in identifying major airports. The Census Bureau also 
received one comment requesting the recognition of rail yards, sea 
ports, and utilities facilities as qualifying as urban territory in 
addition to airports.
    Upon considering the comments received, the Census Bureau will 
retain the Census 2000 criteria to include whole census blocks 
representing airports in urban areas. In order to qualify, an airport 
must report a minimum annual enplanement of 2,500 passengers as 
reported by the FAA for at least one calendar year from 2001 to the 
most current data available for the delineation. All identified 
airports must be currently in service and providing services for the 
urban area in which it is to be included. The 2,500 passenger threshold 
was chosen to provide for a more complete coverage of airports, 
particularly those near smaller initial urban cores. The annual 
passenger boarding data will include only commercial service 
enplanements (primary and nonprimary) to promote consistency with the 
Census 2000 urban area criteria as well as to facilitate a more 
replicable delineation. Also in accordance with the Census 2000 
delineation, the inclusion of airports will represent the last step in 
identifying qualifying urban territory. However, upon further 
consideration and review of data, the Census Bureau has decided to also 
include airports within 0.5 miles of the urban area. This process 
simulates the connection of noncontiguous qualifying territory via the 
hop criteria. All other urban land cover/land use not qualifying 
through residential population count and density measures will be 
represented through the enclave and indentation criteria designed for 
the Census 2000 delineation and supplemented with the impervious 
surface data introduced for the 2010 Census.
Comments Pertaining to the Proposed Criterion Requiring at Least 1,500 
Persons Residing Outside Institutional Group Quarters for an Area To 
Qualify as an Urban Area
    Five commenters supported the proposed criterion requiring that an 
area must encompass at least 1,500 persons living outside institutional 
group quarters (GQs) in order to qualify as an urban area. Two 
commenters opposed this criterion, with one stating that an urban area 
should qualify only on the basis of population residing outside group 
quarters and the other suggesting that qualification as an urban area 
should be based on total population without distinction based on status 
within institutional group quarters. One commenter requested that the 
Census Bureau more closely examine the nature of the land use 
associated with large group quarters before disqualifying territory as 
urban as it contradicts the proposed criteria relating to population 
density and impervious surfaces.
    In response to the comments received, the Census Bureau is 
finalizing the provision that all qualifying urban areas must encompass 
at least 1,500 persons living outside institutional GQs without change 
to avoid the delineation of an urban area comprising only a few census 
blocks in which an institutional GQ was located. The Census Bureau 
recognizes that although the population densities of these areas exceed 
the minimum thresholds specified in the urban area criteria, and the 
total populations exceed 2,500, they lack most of the residential, 
commercial, and infrastructure characteristics typically associated 
with urban territory.
Comments Pertaining to the Proposal to Eliminate the Central Place 
Concept
    The Census Bureau received nine comments regarding the proposed 
elimination of the central place concept from the urban area 
delineation criteria. Eight commenters agreed with the proposal. The 
one commenter who disagreed requested that the Census Bureau should 
continue to identify central places until it is clear that the 
elimination of these criteria will not impact the designation of 
principal cities of metropolitan and micropolitan statistical areas.
    In response to the comments received, the Census Bureau is 
finalizing its proposal to discontinue identifying central places as 
part of the 2010 Census urban area delineation process. The Census 
Bureau notes that the identification of central places is no longer 
necessary for the process of delineating urban areas and can result in 
some central places being split between urban and rural territory. 
Moreover, the Office of Management and Budget (OMB) always had its own 
criteria to identify principal cities as part of the metropolitan and 
micropolitan statistical areas program.\3\ The list of principal cities 
identified by the OMB is quite similar to what would emerge if the 
urban area process created a list of central places. The Census Bureau 
no longer sees a need for a second representation of the same concept 
in its statistical and geographic data products. Principal cities of 
metropolitan and micropolitan statistical areas are identified based on 
different set of criteria and as part of the metropolitan and 
micropolitan area delineation process. This decision will have no 
impact on the metropolitan and micropolitan area delineation process.
---------------------------------------------------------------------------

    \3\ See the ``2010 Standards for Delineating Metropolitan and 
Micropolitan Statistical Areas,'' Federal Register, 75 FR 37246, 
June 28, 2010.
---------------------------------------------------------------------------

Comment Pertaining to the Shape Index Used When Measuring Compactness 
of Census Blocks
    The Census Bureau received one comment concerning the shape index 
proposed to identify census blocks considered compact during the 
delineation of the initial urban area cores. This commenter suggested 
modifying the compactness criterion to only include those census blocks 
that score 0.310 or higher according to the proposed shape index 
formula, as opposed to the proposed shape index value of 0.185 or 
higher.
    The Census Bureau will retain the shape index threshold as 
proposed. Internal research and investigation has shown this to be a 
reasonable metric for measuring compactness for all census blocks 
having the potential to qualify as urban without excluding census 
blocks

[[Page 53037]]

that should be included in an urban area.
Comments Pertaining to the Nonstatistical Uses of Urban Area 
Delineations
    Seventeen commenters expressed concern that the Census Bureau does 
not acknowledge or consider any nonstatistical uses of urban areas when 
developing delineation criteria. Thirteen of these commenters suggested 
that the Census Bureau initiate an inter-agency task force to identify 
the potential negative impacts, particularly on federal funding, 
resulting from changes to the urban area delineation criteria, and 
design mitigation measures and/or solutions to these issues if the 
proposed changes were implemented. These commenters also suggested 
delaying the delineation of urban areas until provisions are adopted 
that would prevent adverse impacts on programs and funding formulas 
relating to urban areas as currently defined.
    Nine commenters stressed the importance of consistency in both 
urban area delineation criteria and status from one decade to another 
to aid long-term planning and policy making. Five of these commenters 
specifically requested that territory defined as urban in Census 2000 
continue to be defined as urban for the 2010 Census.
    Five commenters expressed concern that there are no provisions in 
the delineation criteria for local input and requested the opportunity 
to review and comment on the definition of urban areas before 
boundaries become final. These commenters also expressed concern about 
the automated and inflexible nature of the delineation process and 
suggested that the extent of each urban area should be evaluated 
individually. The Census Bureau also received two comments expressing 
concern that the proposed delineation criteria do not take into account 
local zoning laws and incorporated place boundaries.
    Two commenters criticized the timing for developing the urban area 
delineation criteria. These commenters stated that the methodology is 
flawed because projections related to potential changes in the 
delineation criteria are based on Census 2000 data and geography. These 
commenters suggested that the Census Bureau should delay development of 
the proposed delineation criteria until after 2010 Census data and 
geography become available.
    The Census Bureau received eight requests for the extension of the 
public comment period on the proposed urban area delineation criteria 
to further assess its potential impacts. Additional comments expressed 
difficulty in predicting results of changes to criteria as published in 
the August 24, 2010 Federal Register (75 FR 52174), and requested 
clarification of the proposed urban area delineation criteria. 
Commenters also submitted requests for real-world examples of how 
changes to the urban area delineation criteria would manifest on the 
landscape, maps of the proposed urban areas, and access to the 
delineation software to facilitate better informed public comment.
    In response to the comments received regarding the nonstatistical 
uses of Census urban areas, the Census Bureau recognizes that some 
federal and state agencies use the Census Bureau's urban-rural 
classification for allocating program funds, setting program standards, 
and implementing aspects of their programs. The Census Bureau remains 
committed to an objective, equitable, and consistent nationwide urban 
area delineation, and thus identifies these areas solely for the 
purpose of tabulating and presenting statistical data. This provides 
data users, analysts, and agencies with a baseline set of areas from 
which to work, as appropriate. Given the many programmatic and often 
conflicting or competing uses for Census Bureau-defined urban areas, 
the Census Bureau cannot attempt to take each program into account. 
Therefore, by not taking any one nonstatistical use into account, the 
Census Bureau does not favor one program over another. The Census 
Bureau's designations are used to identify areas to receive funding for 
urban programs and also to identify areas for exclusion from rural-
based programs.
    In building upon the Census 2000 urban area criteria, the Census 
Bureau is developing urban area criteria for the 2010 Census consisting 
of a single set of rules that allow for application of automated 
processes based on the input of standardized nationwide datasets that 
yield consistent results. Rather than defining areas through a process 
of accretion over time, the criteria also provide a better reflection 
of the redistribution of population and how it affects the current 
state of urbanism. This can be done only by reexamining all territory 
that qualified as either urban or rural in earlier censuses based on 
different criteria, geography, and population distribution patterns as 
measured by those censuses. Nonetheless, the Census Bureau will apply 
urban agglomeration split and individual urban area merge criteria to 
ensure, to the greatest extent possible, the continued existence of all 
urbanized areas defined for the Census 2000; although the actual urban 
territory these areas comprise may differ.
    The delineation and production of urban areas and their associated 
data were scheduled to begin in March 2011, to ensure sufficient time 
to delineate and review the urban area definitions and prepare 
geographic information files in time to tabulate statistical data from 
both the 2010 Census and the American Community Survey (ACS). Adherence 
to this schedule prevented any attempts toward a test delineation using 
all of the proposed 2010 urban area criteria for the entire United 
States and Puerto Rico, thus prohibiting the availability of real-world 
examples without showing preference to any particular location. 
Further, this schedule also dictated that the development of the 
delineation software coincided with the development of the proposed and 
final criteria.

IV. Changes to the Proposed Urban Area Criteria for the 2010 Census

    This section of the Federal Register provides information about the 
Census Bureau's decisions on changes that were incorporated into the 
Urban Area Criteria for the 2010 Census in response to the many 
comments received. These decisions benefited greatly from the public 
participation, which served as a reminder that, although identified for 
purposes of collecting, tabulating, and presenting federal statistics, 
the urban areas defined through these criteria represent areas in which 
people reside, work, and spend their lives and to which they attach a 
considerable amount of local pride. In reaching our decisions, the 
Census Bureau took into account the comments received in response to 
the proposed criteria published in the Federal Register on August 24, 
2010, (75 FR 52174), as well as comments received during webinars, 
conference presentations, and meetings with federal, state, and local 
officials, other users of data for urban areas, and additional research 
and investigation conducted by Census Bureau staff.
    The changes made to the proposed criteria in Section II of the 
August 24, 2011, Federal Register Notice, ``Proposed Urban Area 
Criteria for the 2010 Census,'' are as follows:
    1. In Section II, ``Proposed Urban Area Criteria for the 2010 
Census,'' in the introductory paragraph to this section, the Census 
Bureau removed the reference to Island Areas in the first sentence 
because the Census Bureau, in consultation with government officials in 
the Island Areas (American Samoa, Guam, the Commonwealth of the 
Northern Mariana Islands, and the U.S.

[[Page 53038]]

Virgin Islands), is still considering whether to identify urban and 
rural areas for the Island Areas. Census 2000 was the only census in 
which density-based criteria were applied to defining urban areas in 
the Island Areas.
    2. In Section II, ``Proposed Urban Area Criteria for the 2010 
Census,'' subsection B.1, the Census Bureau corrected the initial urban 
area core delineation criteria to better represent the iterative nature 
of these criteria. After the initial urban area core with a population 
density of 1,000 ppsm or more is identified, additional qualifying 
census tracts may be included only if contiguous to other qualifying 
census tracts.
    3. In Section II, ``Proposed Urban Area Criteria for the 2010 
Census,'' subsection B.1, the Census Bureau removed reference to census 
blocks within military installations. Due to imposed restrictions on 
the selection of features that could be used as census block boundaries 
within military installations for Census 2000, blocks on military 
installations that had a population of 2,500 or more were treated as 
having a population density of 1,000 ppsm even if the density was less 
than 1,000 ppsm. Census blocks that had a population greater than 1,000 
and less than 2,500 were treated as hav