Census Tracts for the 2020 Census-Final Criteria, 56277-56284 [2018-24567]

Agencies

• DEPARTMENT OF COMMERCE
• Bureau of the Census

[Federal Register Volume 83, Number 219 (Tuesday, November 13, 2018)]
[Notices]
[Pages 56277-56284]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-24567]


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DEPARTMENT OF COMMERCE

Bureau of the Census

[Docket Number 180927898-8898-01]


Census Tracts for the 2020 Census--Final Criteria

AGENCY: Bureau of the Census, Commerce.

ACTION: Notice of final criteria and program implementation.

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SUMMARY: Census tracts are relatively permanent small-area geographic 
divisions of a county or statistically equivalent entity defined for 
the tabulation and presentation of data from the decennial census and 
selected other statistical programs. The Census Bureau is publishing 
this notice in the Federal Register to announce final criteria for 
defining census tracts for the 2020 Census. Census tracts defined by 
these criteria will also be used to tabulate and publish estimates from 
the American Community Survey (ACS) and potentially data from other 
Bureau of the Census (Census Bureau) censuses and surveys. In addition 
to census tracts, the Participant Statistical Areas Program (PSAP) 
encompasses the review and update of census block groups, census 
designated places, and census county divisions.

DATES: This notice's final criteria will be applicable on December 13, 
2018.

FOR FURTHER INFORMATION CONTACT: Requests for additional information on 
this proposed program should be directed to Vincent Osier at the 
Geographic Standards, Criteria, and Quality Branch, Geography Division, 
U.S. Census Bureau, via email at [email protected] or telephone 
at 301-763-3056.

SUPPLEMENTARY INFORMATION: 

Background

    Census tracts are relatively permanent small-area geographic 
divisions of a county or statistically equivalent entity \1\ defined 
for the tabulation and presentation of data from the decennial census 
and selected other statistical programs. The Census Bureau is 
publishing this notice in the Federal Register to announce final 
criteria for defining census tracts for the 2020 Census. Census tracts 
defined by these criteria will also be used to tabulate and publish 
estimates from the American Community Survey (ACS) \2\ and potentially 
data from other Census Bureau censuses and surveys.
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    \1\ For the Census Bureau's purposes, the term ``county'' 
includes parishes in Louisiana; boroughs, city and boroughs, 
municipalities, and census areas in Alaska; independent cities in 
Maryland, Missouri, Nevada, and Virginia; districts and islands in 
American Samoa; districts in the U.S. Virgin Islands; municipalities 
in the Commonwealth of the Northern Mariana Islands; municipios in 
Puerto Rico; and the areas constituting the District of Columbia and 
Guam. This notice will refer to all these entities collectively as 
``counties''.
    \2\ The ACS is conducted in the United States and in Puerto 
Rico. In Puerto Rico the survey is called the Puerto Rico Community 
Survey. For ease of discussion, throughout this document the term 
ACS is used to represent the surveys conducted in the United States 
and in Puerto Rico.
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    In addition to providing final criteria for census tracts, this 
notice contains a summary of comments received in response to proposed 
criteria published in the Federal Register on February 15, 2018 (83 FR 
6941) as well as the Census Bureau's response to those comments. After 
publication of final criteria in the Federal Register, the Census 
Bureau will offer designated governments or organizations an 
opportunity to review and, if necessary, suggest updates to the 
boundaries and attributes of the census tracts in their geographic area 
through the Participant Statistical Areas Program (PSAP). The program 
also encompasses the review and update of census block groups, census 
designated places, and census county divisions.

I. History of Census Tracts

    In 1905, Dr. Walter Laidlaw originated the concept of permanent, 
small geographic areas as a framework for studying change from one 
decennial census to another in neighborhoods within New York City. For 
the 1910 Census, eight cities--New York, Baltimore, Boston, Chicago, 
Cleveland, Philadelphia, Pittsburgh, and St. Louis--delineated census 
tracts (then termed ``districts'') for the first time. No additional 
jurisdictions delineated census tracts until just prior to the 1930 
Census, when an additional ten cities chose to do so. The increased 
interest in census tracts for the 1930 Census is attributed to the 
promotional efforts of Howard Whipple Green, who was a statistician in 
Cleveland, Ohio, and later the chairman of the American Statistical 
Association's Committee on Census Enumeration Areas. For more than 
twenty-five years, Mr. Green strongly encouraged local citizens, via 
committees, to establish census tracts

[[Page 56278]]

and other census statistical geographic areas. The committees created 
by local citizens were known as Census Tract Committees, later called 
Census Statistical Areas Committees.
    After 1930, the Census Bureau saw the need to standardize the 
delineation, review, and updating of census tracts and published the 
first set of census tract criteria in 1934. The goal of the criteria 
has remained unchanged; they assure comparability and data reliability 
through the standardization of the population thresholds for census 
tracts, as well as requiring that tracts' boundaries follow specific 
types of geographic features that do not change frequently. The Census 
Bureau began publishing census tract data as part of its standard 
tabulations beginning with the 1940 Census. Prior to that time, census 
tract data were published as special tabulations.
    For the 1940 Census, the Census Bureau began publishing census 
block \3\ data for all cities with 50,000 or more people. Census block 
numbers were assigned, where possible, by census tract, but for those 
cities that had not yet delineated census tracts, ``block areas,'' 
called ``block numbering areas'' (BNAs) in later censuses, were created 
to assign census block numbers.
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    \3\ Census blocks are statistical areas bounded by visible 
features, such as streets, roads, streams, and railroad tracks, and 
by non-visible boundaries, such as selected property lines and city, 
township, school district, and county limits and short line-of-sight 
extensions of streets and roads. Census blocks cover the entire 
territory of the United States, Puerto Rico, and the Island Areas.
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    Starting with the 1960 Census, the Census Bureau assumed a greater 
role in promoting and coordinating the delineation, review, and update 
of census tracts. For the 1980 Census, criteria for BNAs were changed 
to make them more comparable in size and shape to census tracts. For 
the 1990 Census, all counties contained either census tracts or BNAs.
    Census 2000 was the first decade in which census tracts were 
defined in all counties. In addition, the Census Bureau increased the 
number of geographic areas whose boundaries could be used as census 
tract boundaries. It also allowed tribal governments of federally 
recognized American Indian tribes with a reservation and/or off-
reservation trust lands to delineate tracts without regard to state 
and/or county boundaries, provided the tribe had a 1990 Census 
population of at least 1,000.
    For the 2010 Census, the Census Bureau adopted changes to census 
tract criteria that recognized their utility as a framework of small 
geographic areas for presenting and analyzing statistical and other 
data for a variety of communities, settlement patterns, and landscapes. 
The Census Bureau augmented its minimum, maximum, and optimum 
population threshold with housing unit thresholds for use in defining 
census tracts for seasonal communities that have no or low population 
on census day (April 1). The Census Bureau formalized criteria for 
census tracts defined for employment centers, airports, parks, large 
water bodies, and other special land uses that had been permitted in 
previous decades, but never specified within the criteria. The Census 
Bureau also established tribal census tracts as a geographic framework 
defined within federally recognized American Indian reservations and 
off-reservation trust lands that is fully separate from the standard 
census tracts defined within counties.

II. Summary of Comments Received in Response to the Proposed Criteria

    The Federal Register published on February 15, 2018 (83 FR 6941) 
requested comment on the proposed census tract criteria for the 2020 
Census. The proposed criteria were unchanged from the final criteria 
adopted for the 2010 Census.
    The Census Bureau received comments from 16 individuals or groups 
of individuals on topics related to (1) use of non-visible political 
boundaries when defining census tracts; (2) use of employment data to 
define census tracts encompassing areas with substantial amounts of 
commercial, industrial, or other non-residential activity for the 
purpose of transportation planning; (3) maintaining historical 
comparability; and (4) accounting for statistical data reliability and 
quality when developing census tract criteria and defining individual 
census tracts. Commenters represented state and local government 
agencies, regional planning organizations and councils of governments, 
state data centers, non-governmental organizations, and academic 
researchers. Comments received by the Census Bureau are summarized 
below, as well as the Census Bureau's response to these comments.

1. Using Non-Visible Minor Civil Division Boundaries in Michigan as 
Census Tract Boundaries

    The Census Bureau received three comments from individuals in 
Michigan noting that non-visible minor civil division (MCD) boundaries 
in Michigan should be permitted to be census tract boundaries for the 
2020 Census as was the case in the past. The commenters correctly noted 
that in Table 1, Acceptable Minor Civil Division and Incorporated Place 
Boundaries, the proposed criteria were in error with regard to 
Michigan. The Census Bureau has corrected the table in the final 
criteria.

2. Defining Census Tracts on the Basis of Employment and Jobs

    The Census Bureau received 14 comments related to defining census 
tracts encompassing areas with concentrations of employment and jobs or 
other types of non-residential uses to improve the utility of census 
tracts for transportation and journey-to-work analysis and planning. 
Eleven commenters suggested adoption of a minimum threshold of 1,200 
workers/jobs (and no maximum or optimum thresholds) to be applied as an 
alternative to the existing minimum population or housing unit 
threshold or in combination with population or housing unit thresholds. 
One commenter supported the use of worker/job counts when defining 
census tracts, but did not specify a minimum threshold. Two commenters 
expressed support for modifying criteria for special use census tracts 
primarily to improve identification of census tracts encompassing areas 
with concentrations of employment. One commenter noted that applying 
employment thresholds was not necessary as the sample design for the 
American Community Survey (which is the source for much of the 
demographic data used in journey-to-work analysis) focused on 
residential population concentrations rather than employment 
concentrations. This commenter suggested that changes to the special 
use census tract land area criteria could achieve the result desired by 
commenters proposing employment thresholds and could provide greater 
flexibility when defining census tracts.
    Based on consideration of the comments received on this topic and 
further discussion with stakeholders in the transportation community, 
the Census Bureau will change its criteria for defining special use 
census tracts to no longer specify minimum land area requirements. 
Special use census tracts should be comparable in land area size to 
surrounding census tracts to assure data reliability and quality when 
reporting on workplace-related data and to avoid data disclosure 
issues. The Census Bureau also recommends that, when defining special 
use census tracts encompassing employment centers and areas with 
concentrations of jobs, PSAP participants should strive for a minimum 
threshold of 1,200 workers/jobs.

[[Page 56279]]

3. Maintaining Historical Comparability

    One commenter noted the importance of maintaining historical 
boundaries of census tracts for chronicling change in the 
sociodemographic characteristics of neighborhoods. The commenter noted 
that, while adherence to specified population thresholds (particularly 
the optimum and maximum population thresholds, which factor in 
decisions to split census tracts) is an important characteristic of 
census tracts, comparability over time also is a critical 
characteristic. Further, allowing census tracts to exceed the optimum 
and maximum thresholds will help mitigate issues related to the large 
sampling error associated with small geographic areas. The commenter 
suggested that by leaving census tract boundaries unchanged (i.e., by 
not splitting census tracts), local governments will be able to 
aggregate census tracts more easily to the neighborhood level, allowing 
for comparability over time as well as more reliable data. The 
commenter further suggested that if census tracts must be merged in 
order to meet the minimum population threshold, then an effort should 
be made to align the boundaries for block groups within the new census 
tract with the boundaries of the former census tracts.
    The Census Bureau agrees with the sentiments expressed by this 
commenter and will continue to allow individual PSAP participants to 
avoid splitting census tracts if they are more concerned about 
historical comparability or statistical data reliability or both. We 
also agree with the suggestion to align block group boundaries with the 
boundaries of former census tracts in those instances in which census 
tracts have been merged and will update the final criteria accordingly.

4. Data Quality as an Explicit Criterion for Census Tracts

    One comment, submitted by a team of researchers, centered around 
the quality and reliability of statistical data for census tracts and 
other small geographic areas. Their concern was that the current 
methodology for updating and defining census tracts, with its focus on 
maintaining historical comparability as well as adherence to the 
optimum threshold of 4,000 persons, results in a framework of small 
geographic areas that may not meet current analytical and policy 
development needs for statistically reliable data. Similar to the 
sentiment expressed by the comment discussed above, this group of 
commenters suggested that in some places and contexts, the population 
size of census tracts should be allowed to increase beyond the maximum 
threshold, adding that these larger units would provide higher quality 
data because they would contain more responses from sample-based 
surveys. However, in their suggestion regarding adoption of explicit 
statistical data quality criteria, the commenters are proposing a 
fundamental change in the process for defining census tracts for data 
dissemination purposes; that is, if a census tract does not achieve the 
quality criterion for a given data release, it would be combined with 
an adjacent tract. The commenters suggest that through this 
combination, the margins of error on the estimates will be reduced, and 
data users will be able to obtain a more reliable estimate for a new 
larger ``census tract'' (encompassing multiple ``sub-tracts'').
    While this is an intriguing idea, the Census Bureau cannot 
implement it at this time. Through the 2020 PSAP, the Census Bureau 
works with participants to update census tract boundaries prior to the 
2020 Census to define a stable geographic framework for tabulating and 
presenting decennial census and ACS data. As we understand it, the 
commenters' proposal would result in a framework of ``preliminary'' 
census tracts that would be combined, as necessary, to meet statistical 
data reliability criteria after data have been tabulated, but prior to 
final release. The Census Bureau needs more time than is available 
prior to the start of the 2020 PSAP delineation process to research 
this proposal and consider any potential data tabulation, data 
disclosure, and analytical implications, particularly if census tracts 
were combined in different ways depending on the specific mix of 
variables presented in a particular data tabulation.

III. General Principles and Criteria for Census Tracts for the 2020 
Census

A. General Principles

    1. The primary goal of the census tract is to provide a set of 
nationally consistent small, statistical geographic units, with stable 
boundaries, that facilitate analysis of data across time. A century of 
census tract use, along with ACS and the averaging of sample data for 
tracts over a five-year span, has shown that continuity and 
comparability in tracts and their boundaries over time are of 
considerable importance to data users. Pursuant to this goal, the 
Census Bureau requests that where a census tract must be updated, for 
example to meet the minimum or maximum population or housing unit 
thresholds, that the outer boundaries of the tract not be changed, but 
rather that a tract be split into two or more tracts, or merged with an 
adjacent tract. The Census Bureau discourages changes to tract 
boundaries (that is, ``retracting''), except in specified 
circumstances, which the Census Bureau will review on a case-by-case 
basis.
    2. In order to ensure a minimal level of reliability in sample data 
and minimize potential disclosures of sensitive information, a census 
tract should contain at least 1,200 people or at least 480 housing 
units at minimum, and 8,000 people or 3,200 housing units at maximum. 
PSAP participants should aim to create census tracts that meet the 
optimal population of 4,000 or 1,600 housing units and maintain the 
minimum thresholds unless it is flagged as a special use tract 
(discussed below), or is coextensive with a county with fewer than 
1,200 people. The housing unit criterion is used to accommodate areas 
that are occupied seasonally and may otherwise show a discrepancy 
between decennial and ACS figures.\4\
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    \4\ ``Occupied seasonally'' refers to seasonal communities in 
which residents often are not present on the date of the decennial 
census, but will be present at other times of the year and for which 
estimates may be reflected in the ACS. The ACS is designed to 
produce local area data as of a 12-month period estimate (or an 
average).
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    3. The Census Bureau recognizes that there are significant 
geographic areas that are characterized by unique populations (e.g., 
prisons or universities) or not characterized by residential 
populations at all (e.g., National Parks, large bodies of water, or 
employment centers) which local participants may wish to exclude from 
populated census tracts for either analytical or cartographic purposes. 
These areas may be designated as special use census tracts to 
distinguish them from standard populated census tracts. Special land 
and/or water use census tracts are not required, but if delineated they 
must be designated as a specific type of special use (discussed below), 
have an official name, ideally have no residential population or 
housing units or at least meet all minimum population or housing 
thresholds mention above, and must not create noncontiguous census 
tracts. While there are no longer minimum land area measurement 
thresholds for special use tracts in urban or rural areas, such census 
tracts should be comparable in size to surrounding census tracts, 
particularly if defined to encompass employment centers or other areas 
containing a greater concentration of jobs than residents. The Census 
Bureau recognizes that some special use areas not intended for 
residential

[[Page 56280]]

population, such as parks, may contain some minimal population, such as 
caretakers or those experiencing homelessness. Since the primary 
purpose of census tracts is to help provide high-quality statistical 
data about the population, the participant and the Census Bureau must 
decide if a special use tract would be useful in such a situation.
    4. To facilitate the analysis of data for American Indian tribes, 
and to recognize their unique governmental status, program participants 
are encouraged to merge, split, or redefine census tracts to avoid 
unnecessarily splitting American Indian reservations (AIRs) and off-
reservation trust lands (ORTLs). Each contiguous AIR and/or ORTL should 
be included, along with any necessary territory outside the AIR and/or 
ORTL, within a single census tract or as few census tracts as possible 
for the 2020 Census. This is the only situation in which retracting is 
encouraged (Figure 1).
[GRAPHIC] [TIFF OMITTED] TN13NO18.096

B. Criteria

    The criteria herein apply to the United States, including federally 
recognized AIRs and ORTLs, Puerto Rico, and the Island Areas.\5\ The 
Census Bureau may modify and, if necessary, reject any proposals for 
census tracts that do not meet the published criteria. In addition, the 
Census Bureau reserves the right to modify the boundaries and 
attributes of census tracts as needed to meet the published criteria 
and/or maintain geographic relationships before or after the final 
tabulation geography is set for the 2020 Census.
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    \5\ For Census Bureau purposes, the United States typically 
refers to only the fifty states and the District of Columbia, and 
does not include the U.S. territories (Puerto Rico, the Island 
Areas, and the U.S. Minor Outlying Islands). The Island Areas 
includes American Samoa, the Commonwealth of the Northern Mariana 
Islands, Guam, and the U.S. Virgin Islands. The U.S. Minor Outlying 
Islands are an aggregation of nine U.S. territories: Baker Island, 
Howland Island, Jarvis Island, Johnston Atoll, Kingman Reef, Midway 
Islands, Navassa Island, Palmyra Atoll, and Wake Island.
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    The Census Bureau sets forth the following criteria for use in 
reviewing, updating, and delineating 2020 Census tracts:
    5. Census tracts must not cross county or state boundaries.
    This criterion takes precedence over all other criteria or 
requirements (except for tribal tracts on federally recognized AIRs 
and/or ORTLs).
    6. Census tracts must cover the entire land and water area of a 
county.
    7. Census tracts must comprise a reasonably compact and contiguous 
land area.
    Noncontiguous boundaries are permitted only where a contiguous area 
or inaccessible area would not meet population or housing unit count 
requirements for a separate census tract, in which case the 
noncontiguous or inaccessible area must be combined within an adjacent 
or proximate tract. For example, an island that does not meet the 
minimum population threshold for recognition as a separate census tract 
should be combined with other proximate land to form a single, 
contiguous census tract. Each case will be reviewed and accepted at the 
Census Bureau's discretion.
    8. Census tract boundaries should follow visible and identifiable 
features.
    To make the location of census tract boundaries less ambiguous, 
wherever possible, tract boundaries should follow significant, visible, 
easily identifiable features. The use of visible features facilitates 
the location and identification of census tract boundaries in the 
field, both on the ground and in imagery. The selection of permanent 
physical features also increases the stability of the boundaries over 
time, as the locations of many visible features in the landscape tend 
to change infrequently. If census tract boundaries are changed, they 
should not be moved from a more

[[Page 56281]]

significant feature (e.g., a highway or a major river) to a less 
significant feature (e.g., a neighborhood road or a small tributary 
stream). By definition, state and county boundaries must be used as 
census tract boundaries. The Census Bureau also permits the use of 
incorporated place and minor civil division (MCD) boundaries in states 
where those boundaries tend to remain unchanged over time (see Table 
1).
    The following features are preferred as census tract boundaries for 
the 2020 Census:
    a. State and county boundaries must always be census tract 
boundaries. This criterion takes precedence over all other boundary 
criteria or requirements.
    b. AIR and ORTL boundaries.
    c. Visible, perennial, stable, relatively permanent natural and 
constructed features, such as roads, shorelines, rivers, perennial 
streams and canals, railroad tracks, or above-ground high-tension power 
lines.
    d. Boundaries of legal and administrative entities in selected 
states. Table 1 identifies by state which MCD and incorporated place 
boundaries may be used as census tract boundaries.
    e. Additionally, the following legally defined, administrative 
boundaries would be permitted as census tract boundaries:
    i. Barrio, barrio-pueblo, and sub-barrio boundaries in Puerto Rico;
    ii. Census subdistrict and estate boundaries in the U.S. Virgin 
Islands;
    iii. County and island boundaries (both MCD equivalents) in 
American Samoa;
    iv. Election district boundaries in Guam;
    v. Municipal district boundaries in the Commonwealth of the 
Northern Mariana Islands; and,
    vi. Alaska Native Regional Corporation boundaries in Alaska, at the 
discretion of the Census Bureau, insofar as such boundaries are 
unambiguous for allocating living quarters as part of 2020 Census 
activities.
    f. The boundaries of large parks, forests, airports, 
penitentiaries/prisons, and/or military installations, provided the 
boundaries are clearly marked or easily recognized in the field, in 
imagery, and on the ground.
    g. When acceptable visible and governmental boundary features are 
not available for use as census tract boundaries, the Census Bureau 
may, at its discretion, approve other nonstandard visible features, 
such as major ridgelines, above-ground pipelines, intermittent streams, 
or fence lines. The Census Bureau may also accept, on a case-by-case 
basis, relatively short stretches of boundaries of selected nonstandard 
and potentially nonvisible features, such as cadastral and parcel 
boundaries or the straight-line extensions or other lines-of-sight 
between acceptable visible features.

                Table 1--Acceptable Minor Civil Division (MCD) and Incorporated Place Boundaries
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                                                                Boundaries of
                                                                MCDs not  co-
                                                                incident with         All         Only conjoint
                                                  All MCD       the boundaries    incorporated     incorporated
                    State                        boundaries    of incorporated       place            place
                                                                 places that       boundaries       boundaries
                                                                themselves are
                                                                     MCDs
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Alabama.....................................  ...............  ...............  ...............               X
Alaska......................................  ...............  ...............  ...............               X
Arizona.....................................  ...............  ...............  ...............               X
Arkansas....................................  ...............  ...............  ...............               X
California..................................  ...............  ...............  ...............               X
Colorado....................................  ...............  ...............  ...............               X
Connecticut.................................               X   ...............               X   ...............
Delaware....................................  ...............  ...............  ...............               X
Florida.....................................  ...............  ...............  ...............               X
Georgia.....................................  ...............  ...............  ...............               X
Hawaii......................................  ...............  ...............  ...............  ...............
Idaho.......................................  ...............  ...............  ...............               X
Illinois....................................  ...............           X \a\   ...............               X
Indiana.....................................               X   ...............  ...............               X
Iowa........................................  ...............               X   ...............               X
Kansas......................................  ...............               X   ...............               X
Kentucky....................................  ...............  ...............  ...............               X
Louisiana...................................  ...............  ...............  ...............               X
Maine.......................................               X   ...............               X   ...............
Maryland....................................  ...............  ...............  ...............               X
Massachusetts...............................               X   ...............               X   ...............
Michigan....................................  ...............               X   ...............               X
Minnesota...................................  ...............               X   ...............               X
Mississippi.................................  ...............  ...............  ...............               X
Missouri....................................  ...............           X \b\   ...............               X
Montana.....................................  ...............  ...............  ...............               X
Nebraska....................................  ...............           X \a\   ...............               X
Nevada......................................  ...............  ...............  ...............               X
New Hampshire...............................               X   ...............               X   ...............
New Jersey..................................               X   ...............               X   ...............
New Mexico..................................  ...............  ...............  ...............               X
New York....................................               X   ...............               X   ...............
North Carolina..............................  ...............  ...............  ...............               X
North Dakota................................  ...............               X   ...............               X
Ohio........................................  ...............               X   ...............               X
Oklahoma....................................  ...............  ...............  ...............               X
Oregon......................................  ...............  ...............  ...............               X

[[Page 56282]]

 
Pennsylvania................................               X   ...............               X   ...............
Rhode Island................................               X   ...............               X   ...............
South Carolina..............................  ...............  ...............  ...............               X
South Dakota................................  ...............               X   ...............               X
Tennessee...................................  ...............  ...............  ...............               X
Texas.......................................  ...............  ...............  ...............               X
Utah........................................  ...............  ...............  ...............               X
Vermont.....................................               X   ...............               X   ...............
Virginia....................................  ...............  ...............  ...............               X
Washington..................................  ...............  ...............  ...............               X
West Virginia...............................  ...............  ...............  ...............               X
Wisconsin...................................  ...............               X   ...............               X
Wyoming.....................................  ...............  ...............  ...............               X
----------------------------------------------------------------------------------------------------------------
\a\ Townships only.
\b\ Governmental townships only.

9. Population, Housing Unit, and Area Measurement Thresholds
    The following are the population, housing unit, and area 
measurement threshold criteria for census tracts (as summarized in 
Table 2). The same population and housing unit thresholds apply to all 
types of non-special use census tracts, including census tracts 
delineated for AIRs and ORTLs, the Island Areas, and encompassing group 
quarters, military installations, and institutions.

                                        Table 2--Census Tract Thresholds
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        Census tract type           Threshold type          Optimum             Minimum             Maximum
----------------------------------------------------------------------------------------------------------------
Standard & tribal census tracts.  Population          4,000.............  1,200.............  8,000.
                                   threshold.         1,600.............  480...............  3,200.
                                  Housing unit
                                   threshold.
Special use census tracts.......  Area measurement..  At least            At least            At least
                                                       comparable in       comparable in       comparable in
                                                       land area size to   land area size to   land area size to
                                                       surrounding         surrounding         surrounding
                                                       census tracts.      census tracts.      census tracts.
                                                     -----------------------------------------------------------
                                  Employment                  Suggested minimum of 1,200 workers or jobs.
                                   threshold
                                   (suggested).
----------------------------------------------------------------------------------------------------------------

    a. 2010 Census population counts should be used in census tract 
review in most cases. Housing unit counts should be used for census 
tracts in seasonal communities that have little or no population on 
Census Day (April 1). Locally produced population and housing unit 
estimates can be used when reviewing and updating census tracts, 
especially in areas that have experienced considerable growth since the 
2010 Census.
    b. The housing unit thresholds are based on a national average of 
2.5 persons per household. The Census Bureau recognizes that there are 
local and regional variations to this average, and will take this into 
consideration when reviewing all census tract proposals.
    c. Any census tract with a population or housing unit count less 
than the minimum threshold should be merged with an adjacent census 
tract to form a single tract with at least 1,200 people or at least 480 
housing units (Figure 2). The Census Bureau recognizes the complexity 
that exists between meeting the optimum population or housing unit 
threshold in a census tract and maintaining census tract comparability 
over time. For example, if the population or housing unit count based 
on 2010 Census data was below the minimum thresholds, but significant 
growth has occurred since 2010 or is expected before 2020 for a census 
tract, the census tract should not be merged with another census tract. 
Supporting evidence may be requested by the Census Bureau. However, if 
the census tract's population does not increase as expected and does 
not meet either the minimum population or housing unit thresholds for 
2020, this may adversely affect the reliability and availability of any 
sample estimates for that census tract. For this reason, the Census 
Bureau suggests merging the census tract with another adjacent census 
tract if there is a possibility that anticipated growth will not be 
sufficient to meet minimum thresholds. When merging census tracts, the 
Census Bureau suggests retaining the former census tract boundaries as 
boundaries for block groups within the newly defined census tract to 
facilitate historical analysis.

[[Page 56283]]

[GRAPHIC] [TIFF OMITTED] TN13NO18.097

    d. For the 2020 Census, the Census Bureau will allow the 
delineation of special use census tracts, but they are not required. A 
special use census tract must be designated as a specific use type 
(e.g., state park), must have an official name (e.g., Jay Cooke State 
Park), have no (or very little) residential population or meet 
population or housing unit thresholds, and must not create a 
noncontiguous census tract. In some instances, multiple areas can be 
combined to form a single special use census tract if the land use or 
land management characteristics are similar, such as a special use 
census tract comprising an area with a concentration of employment or 
adjacent federal and state parks. Any resulting special use census 
tract should be at least as large in area as the surrounding standard, 
populated census tracts.
10. Identification of Census Tracts
    a. A census tract has a basic census tract identifier composed of 
no more than four digits and may have a two-digit decimal suffix.
    b. The range of acceptable basic census tract identifiers for the 
2020 Census is from 1 to 9989 (see 6.c. below for exceptions); special 
use census tracts delineated specifically to complete coverage of large 
water bodies will be numbered from 9950 to 9989 in each county.
    c. Census tracts delineated within or to primarily encompass AIRs 
and/or ORTLs should be numbered from 9400 to 9499.
    d. Census tract identifiers must be unique within each county.
    e. Once used, census tract identifiers cannot be reused in a 
subsequent census to reference a completely different area within a 
county. If a census tract is split, each portion may keep the same 
basic 4-digit identifier, but each portion must be given a unique 
suffix. If a census tract that was suffixed for 2010 Census is split, 
each portion must be given a new suffix.
    f. The range of acceptable census tract suffixes is .01 to .98.
11. Census Tract Types
    Table 3 provides a summary of the types of census tracts (with 
their respective population, housing unit, and area measurement 
thresholds) that the Census Bureau will use for the 2020 Census.

                                     Table 3--Summary of Census Tract Types
----------------------------------------------------------------------------------------------------------------
                                    Distinction from         Population        Housing unit     Area measurement
       Census tract type          standard census tract      thresholds         thresholds         thresholds
----------------------------------------------------------------------------------------------------------------
Standard census tract..........  ......................  Optimum: 4,000;    Optimum: 1,600;    None.
                                                          Min: 1,200; Max:   Min: 480; Max:
                                                          8,000.             3,200.
Tribal census tract............  Tribal census tracts    Optimum: 4,000;    Optimum: 1,600;    None.
                                  are conceptually        Min: 1,200; Max:   Min: 480; Max:
                                  similar and             8,000.             3,200.
                                  equivalent to census
                                  tracts defined within
                                  the standard state-
                                  county-tract
                                  geographic hierarchy
                                  used for tabulating
                                  and publishing
                                  statistical data.
Special use census tract.......  A census tract          None (or very      None (or very      At least
                                  encompassing an         little) or         little) or         comparable in
                                  employment center,      within the         within the         size to
                                  large airport, public   standard census    standard census    surrounding
                                  park, public forest,    tract threshold.   tract threshold.   standard census
                                  or large water body                                           tracts.
                                  with no (or very
                                  little) population or
                                  housing units.
----------------------------------------------------------------------------------------------------------------

B. Tribal Census Tracts

    Tribal census tracts are statistical geographic entities defined by 
the Census Bureau in cooperation with tribal officials to provide 
meaningful, relevant, and reliable data for small geographic areas 
within the boundaries of federally recognized AIRs and/or ORTLs. As 
such, they recognize the unique statistical data needs of federally 
recognized American Indian tribes. The delineation of tribal census 
tracts allows for an unambiguous presentation of census tract-level 
data specific to the federally recognized AIR and/or ORTL without the 
imposition of state or county boundaries, which might artificially 
separate American Indian populations located within a single AIR and/or 
ORTL. To this end, the American

[[Page 56284]]

Indian tribal participant may define tribal census tracts that cross 
county or state boundaries, or both. For federally recognized American 
Indian tribes with AIRs and/or ORTLs that have more than 2,400 
residents, the Census Bureau will offer the tribal government the 
opportunity to delineate tribal census tracts and other tribal 
statistical geography on their AIR and/or ORTL. For federally 
recognized tribes with an AIR and/or ORTL with fewer than 2,400 
residents, the Census Bureau will define one tribal census tract 
coextensive with the AIR and/or ORTL. Tribal census tracts must be 
delineated to meet all other census tract criteria, and must be 
identified uniquely to clearly distinguish them from county-based 
census tracts. Tribal census tracts are conceptually similar and 
equivalent to census tracts defined within the standard state-county-
tract geographic hierarchy used for tabulating and publishing 
statistical data.
    In order to provide meaningful statistical geographic areas within 
the AIR and/or ORTL, as well as make meaningful and reliable data 
available for these areas and their populations, tribal census tract 
geography is maintained separately from standard county-based census 
tracts. This change was first introduced for the 2010 Census, creating 
standard, county-based census tracts nationwide and maintaining tribal 
census tracts as a completely separate set of geography from standard 
census tracts for both geographic and data presentation purposes. The 
change eliminated, in part, the reliability and availability data 
issues for the tribal census tracts and the derived standard census 
tracts that were present in Census 2000. \6\
---------------------------------------------------------------------------

    \6\ For Census 2000, tribal tracts were defined for federally 
recognized AIRs and/or ORTLs and standard census tracts were 
identified by superimposing county and state boundaries onto the 
tribal tracts. For Census 2000 products in which data were presented 
by state and county, the standard state-county-census tract 
hierarchy was maintained, even for territory contained within an AIR 
and/or ORTL. In such instances, the state-county portions of a 
tribal tract were identified as individual census tracts. These 
standard census tracts may not have met the minimum population 
thresholds, potentially limiting sample data reliability or 
availability for both the tribal tract and the derived standard 
census tracts.
---------------------------------------------------------------------------

    As with standard census tracts submitted through this program, the 
tribal census tracts are submitted to the Census Bureau, and are 
subject to review to ensure compliance with the published criteria. 
Detailed criteria pertaining to tribal census tracts will be published 
in a separate Federal Register notice pertaining to all American Indian 
areas, including statistical areas defined through the PSAP.

IV. Definitions of Key Terms

    Alaska Native Regional Corporation (ANRC)--A corporate geographic 
area established under the Alaska Native Claims Settlement Act (Pub. L. 
92-203, 85 Stat. 688 (1971)) to conduct both the business and nonprofit 
affairs of Alaska Natives. Twelve ANRCs cover the entire state of 
Alaska except for the Annette Island Reserve.
    American Indian off-reservation trust land (ORTL)--An area of land 
located outside the boundaries of an AIR, whose boundaries are 
established by deed, and which are held in trust by the U.S. federal 
government for a federally recognized American Indian tribe or members 
of that tribe.
    American Indian reservation (AIR)--An area of land with boundaries 
established by final treaty, statute, executive order, and/or court 
order and over which a federally recognized American Indian tribal 
government has governmental authority. Along with ``reservation,'' 
designations such as colonies, communities, pueblos, rancherias, and 
reserves apply to AIRs.
    Census block--Census blocks are statistical areas bounded by 
visible features, such as streets, roads, streams, and railroad tracks, 
and by non-visible boundaries, such as selected property lines and 
city, township, school district, and county limits and short line-of-
sight extensions of streets and roads. Census blocks cover the entire 
territory of the United States, Puerto Rico, and the Island Areas.
    Conjoint--A description of a boundary line shared by two adjacent 
geographic entities.
    Contiguous--A description of areas sharing common boundary lines, 
more than a single point, such that the areas, when combined, form a 
single piece of territory. Noncontiguous areas form disjoint pieces.
    Group quarters--A location where people live or stay, in a group 
living arrangement, that is owned or managed by an entity or 
organization providing housing and/or services for the residents. This 
is not a typical household-type living arrangement. These services may 
include custodial or medical care as well as other types of assistance, 
and residency is commonly restricted to those receiving these services. 
People living in group quarters are usually not related to each other. 
Group quarters include such places as college residence halls, 
residential treatment centers, skilled nursing facilities, group homes, 
military barracks, correctional facilities, and workers' dormitories.
    Incorporated place--A type of governmental unit, incorporated under 
state law as a city, town (except in New England, New York, and 
Wisconsin), borough (except in Alaska and New York), or village, 
generally to provide governmental services for a concentration of 
people within legally prescribed boundaries.
    Minor civil division (MCD)--The primary governmental or 
administrative division of a county in 28 states and the Island Areas 
having legal boundaries, names, and descriptions. The MCDs represent 
many different types of legal entities with a wide variety of 
characteristics, powers, and functions depending on the state and type 
of MCD. In some states, some or all of the incorporated places also 
constitute MCDs.
    Nonvisible feature--A map feature that is not visible on the ground 
such as a city or county boundary through space, a property line, or 
line-of-sight extension of a road.
    Retracting--Substantially changing the boundaries of a census tract 
so that comparability over time is not maintained.
    Special use census tract--Type of census tract that must be 
designated as a specific use type (e.g., state park or large lake) and 
have an official name (e.g., Jay Cooke State Park or Lake Minnetonka), 
should have no (or very little) population or housing units, and must 
not create a noncontiguous census tract. If delineated in a densely 
populated, urban area, a special use census tract must have an area of 
at least one square mile. If delineated completely outside an urban 
area, a special use census tract must have an area of at least 10 
square miles.
    Visible feature--A map feature that can be seen on the ground and 
in imagery, such as a road, railroad track, major above-ground 
transmission line or pipeline, river, stream, shoreline, fence, sharply 
defined mountain ridge, or cliff. A nonstandard visible feature is a 
feature that may not be clearly defined on the ground (such as a 
ridge), may be seasonal (such as an intermittent stream), or may be 
relatively impermanent (such as a fence). The Census Bureau generally 
requests verification that nonstandard features used as boundaries for 
the PSAP geographic areas pose no problem in their location during 
field work.

    Dated: October 30, 2018.
Ron S. Jarmin,
Deputy Director, Performing the Non-Exclusive Functions and Duties of 
the Director, Bureau of the Census.
[FR Doc. 2018-24567 Filed 11-9-18; 8:45 am]
 BILLING CODE 3510-07-P