Block Groups for the 2020 Census-Final Criteria, 56293-56298 [2018-24570]

Agencies

• DEPARTMENT OF COMMERCE
• Bureau of the Census

[Federal Register Volume 83, Number 219 (Tuesday, November 13, 2018)]
[Notices]
[Pages 56293-56298]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-24570]


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DEPARTMENT OF COMMERCE

Bureau of the Census

[Docket Number 180926886-8886-01]


Block Groups 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: Block groups are statistical geographic subdivisions of a 
census tract defined for the tabulation and presentation of data from 
the decennial census and selected other statistical programs. Block 
groups also will be used to tabulate and publish estimates from the 
American Community Survey (ACS) after 2020 and potentially data from 
other Bureau of the Census (Census Bureau) censuses and surveys. The 
Census Bureau is publishing this notice in the Federal Register to 
announce final criteria for defining block groups for the 2020 Census 
Participant Statistical Areas Program (PSAP). In addition to block 
groups, the program also encompasses the review and update of census 
tracts, 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 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 by telephone at 
301-763-3056.

SUPPLEMENTARY INFORMATION: 

Background

    Block groups are statistical geographic subdivisions of a census 
tract defined for the tabulation and presentation of data from the 
decennial census and selected other statistical programs. Block groups 
also will be used to tabulate and publish estimates from the American 
Community Survey (ACS) \1\ after 2020 and potentially data from other 
Bureau of the Census (Census Bureau) censuses and surveys.
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    \1\ 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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    The Census Bureau is publishing this notice in the Federal Register 
to announce final criteria for defining block groups for the 2020 
Census. In addition to providing final criteria for block groups, this 
notice also contains a summary of comments received in response to 
proposed criteria published in the Federal Register on February 15, 
2018 (83 FR 6937), as well as the Census Bureau's response to those 
comments. After publication of this 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 block groups in their 
geographic area under the Participant Statistical Areas Program (PSAP). 
In addition to block groups, the program also encompasses the review 
and update of census tracts, census designated places, and census 
county divisions. The Census Bureau published a notice, explaining PSAP 
process and participation, in the Federal Register on November 28, 2017 
(82 FR 56208).

I. History of Block Groups

    The Census Bureau first delineated block groups as statistical 
geographic divisions of census tracts for the 1970 Census, comprising 
contiguous combinations of census blocks for data presentation 
purposes. At that time, census block groups only existed in urbanized 
areas in which census blocks were defined. Block groups were defined 
without regard to political and administrative boundaries, with an 
average population of 1,000, and to be approximately equal in area.
    As use of census block, block group, and census tract data 
increased among data users, the Census Bureau expanded these programs 
to cover additional geographic areas while redefining the population 
threshold criteria to more adequately suit data users' needs. The 1990 
Census was the first in which census blocks and block groups were 
defined throughout the entirety of the United States, Puerto Rico, and 
the Island Areas. For the 2000 Census, as with census tracts, the 
Census Bureau increased the number of geographic areas whose boundaries 
could be used as block group boundaries, and allowed tribal governments 
of federally recognized American Indian tribes with a reservation and/
or off-reservation trust lands to delineate tribal block groups 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 block 
group criteria that recognized their utility as a framework of small 
geographic areas and established tribal block groups as a geographic 
framework for presenting and analyzing statistical and other data for a 
variety of communities, settlement patterns, and landscapes. The Census 
Bureau augmented its minimum and maximum population threshold with 
housing unit thresholds for use in defining block groups for seasonal 
communities that have no or low population on census day (April 1). In 
addition, the Census Bureau formalized criteria for block groups 
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 block groups as a geographic framework defined 
within federally recognized American Indian reservations and off-
reservation trust lands that is fully separate from the standard block 
groups defined within counties.

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

    The Federal Register notice published on February 15, 2018 (83 FR 
6937) requested comment on the proposed block group 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 on one or 
more topics related to (1) use of non-visible political boundaries when 
defining block groups, (2) use of employment data to define block 
groups

[[Page 56294]]

encompassing areas with substantial amounts of commercial, industrial, 
or other non-residential activity for the purpose of transportation 
planning, and (3) defining block groups to align with former census 
tract boundaries when census tracts are merged. Commenters represented 
state and local government agencies, regional planning organizations 
and councils of governments, state data centers, and non-governmental 
organizations. 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 
Block Group Boundaries
    The Census Bureau received three comments from individuals in 
Michigan noting that all minor civil division (MCD) boundaries in 
Michigan should be permitted to be block group 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 Block Groups on the Basis of Employment and Jobs
    The Census Bureau received 14 comments related to defining block 
groups encompassing areas with concentrations of employment and jobs or 
other types of non-residential uses to improve the utility of block 
groups for transportation and journey-to-work analysis and planning. 
Eleven commenters suggested adoption of a minimum threshold of 600 
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 
block groups, but did not specify a minimum threshold. Two commenters 
expressed support for modifying criteria for special use block groups 
primarily to improve identification of block groups encompassing areas 
with concentrations of employment. One of these commenters 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 and not employment 
concentrations. Changes to the special use block group criteria could 
achieve the result desired by commenters proposing employment 
thresholds and could also provide greater flexibility when defining 
block groups.
    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 
block groups to no longer specify minimum land area requirements. 
Special use block groups should be comparable in land area size to 
surrounding block groups so as 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 block groups encompassing employment centers and areas with 
concentrations of jobs, PSAP participants should strive for a minimum 
threshold of 600 workers/jobs.
3. Defining Block Groups To Follow Former Census Tract Boundaries
    One commenter proposed that, when census tracts are merged, 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 
that were merged. The commenter noted that this would facilitate 
historical comparisons of data, particularly when chronicling change in 
the sociodemographic characteristics of neighborhoods, allowing data 
users to use block group data to bridge back to previous decades' 
census tracts.
    The Census Bureau agrees with the sentiments expressed by this 
commenter. 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 both 
the final block group and final census tract criteria accordingly.

III. General Principles and Criteria for Block Groups for the 2020 
Census

A. General Principles

    1. Block groups are statistical geographic subdivisions of a census 
tract and are the smallest geographic areas for which the Census Bureau 
provides sample data, primarily from the ACS 5-year period estimates.
    2. Block groups form the geographic framework within which census 
blocks are numbered.
    3. In order to ensure a minimal level of reliability in sample data 
and minimize potential disclosures of sensitive information, a block 
group should contain either at least 600 people or at least 240 housing 
units at minimum, and 3,000 people or 1,200 housing units at maximum. 
The housing unit criterion is used to accommodate areas that are 
occupied seasonally and may otherwise show a discrepancy between 
decennial and ACS figures. \2\ For the ACS, block groups are not 
designed to be used individually, rather they provide a smaller 
geographic area than census tracts that allow data users to combine 
them to create larger geographic areas that may be more meaningful for 
their specific use.
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    \2\ ``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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    4. The Census Bureau also 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 or large bodies of water) 
which local participants may wish to exclude from populated block 
groups for either analytical or cartographic purposes. These areas may 
be designated as special use block groups to distinguish them from 
standard populated block groups. Special land and/or water use block 
groups 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 block groups. While there are no longer 
minimum land area measurement thresholds for special uses block groups 
in urban or rural areas, such block groups should be comparable in size 
to surrounding block groups, 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 population, such as parks, may 
contain some minimal population, such as caretakers or the homeless, 
but since the primary purpose of block groups is to help provide high-
quality statistical data about the population, the participant and the 
Census Bureau must decide if a special use block group would be useful 
in such a situation.

[[Page 56295]]

B. Criteria

    The criteria herein apply to the United States, including federally 
recognized American Indian reservations (AIRs) and off-reservation 
trust lands (ORTLs), Puerto Rico, and the Island Areas. \3\ The Census 
Bureau may modify and, if necessary, reject any proposals for block 
groups that do not meet the published criteria. In addition, the Census 
Bureau reserves the right to modify the boundaries and attributes of 
block groups 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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    \3\ 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 block groups:
    1. Block groups must not cross census tract boundaries.
    This criterion takes precedence over all other criteria or 
requirements. By definition, because census tracts cannot cross county 
\4\ and state boundaries, neither can block groups. It is only 
permissible to define a block group with fewer than 600 people in a 
county that has a population less than 600, coextensive with a special 
use census tract, or as a special use block group delineated within a 
standard census tract.
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    \4\ 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''.
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    2. Block groups must cover the entire land and water area of each 
census tract.
    Because census tracts must cover the entire area of a county, by 
definition, block groups also must cover the entire area of each census 
tract within each county.
    3. A block group 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 block group, in which case the 
noncontiguous or inaccessible area must be combined within an adjacent 
or proximate block group. For example, an island that does not meet the 
minimum population threshold for recognition as a separate block group 
should be combined with other proximate land to form a single block 
group. Each case will be reviewed and accepted at the Census Bureau's 
discretion.
    4. Block group boundaries should follow visible and identifiable 
features.
    To make the location of block group boundaries less ambiguous, 
wherever possible, block group boundaries should follow significant, 
visible, easily identifiable features. The use of visible features 
facilitates the location and identification of block group 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 block group boundaries are 
changed, they should not be moved from a more 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). The Census Bureau 
also requires the use of state and county boundaries in all states to 
be used as census tract and block group 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 block group boundaries for 
the 2020 Census:
    a. State, county, and census tract boundaries must always be block 
group 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 block group boundaries.
    e. Additionally, the following legally defined, administrative 
boundaries are permitted as block group boundaries:
    i. Barrio, barrio-pueblo, and subbarrio 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 block group 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.

[[Page 56296]]



                Table 1--Acceptable Minor Civil Division (MCD) and Incorporated Place Boundaries
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                                                                Boundaries of
                                                                   MCDs not
                                                               coincident 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
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
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\a\ Townships only.
\b\ Governmental townships only.

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

[[Page 56297]]



                                         Table 2--Block Group Thresholds
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           Block group type                Threshold types              Minimum                  Maximum
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Standard & tribal block groups.......  Population thresholds..  600....................  3,000
                                       Housing unit thresholds  240....................  1,200
Special use block groups.............  Area measurement.......  At least comparable in   At least comparable in
                                                                 land area size to        land area size to
                                                                 surrounding block        surrounding block
                                                                 groups.                  groups.
                                                               -------------------------------------------------
                                       Population thresholds..    None (or very little), or must be within the
                                                                         standard block group thresholds.
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    a. 2010 Census population counts should be used in census block 
group review in most cases. Housing unit counts should be used for 
block groups 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 block groups, 
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 people per household. The Census Bureau recognizes that there are 
regional variations to this average, and will take this into 
consideration when reviewing all census block group proposals.
    c. For the 2020 Census, the Census Bureau will allow the 
delineation of special use census tracts, and special use block groups 
will be created coextensive with these special use census tracts, but 
they are not required. A special use census tract, and hence a special 
use block group, 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/block 
group. In some instances, multiple areas can be combined to form a 
single special land use census tract/block group if the land management 
characteristics are similar, such as a special land use census tract/
block group comprising an area with a concentration of employment or 
adjacent federal and state parks. Any resulting special use census 
tract/block group should be at least as large in area as the 
surrounding adjacent standard, populated census tracts/block groups.
6. Identification of Block Groups
    a. A block group encompasses a cluster of census blocks. Each 
standard block group is identified using a single-digit number that 
will correspond to the first digit in the number of each census block 
encompassed by the block group. For example, block group 3 includes all 
census blocks numbered in the 3000 range within a single census tract.
    b. The range of acceptable standard block group numbers is 1 
through 9.
    c. Block group numbers must be unique within a census tract.
7. Block Group Types
    Table 3 provides a summary of the types of block groups (with their 
respective population, housing unit, and area measurement thresholds) 
that the Census Bureau will use for the 2020 Census.

                                      Table 3--Summary of Block Group Types
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                                    Distinction from         Population        Housing unit     Area measurement
       Block group types          standard block groups      thresholds         thresholds         thresholds
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Standard block groups..........  ......................  Min: 600, Max:     Min: 240, Max:     None.
                                                          3,000.             1,200.
Tribal block groups............  Tribal block groups     Min: 600, Max:     Min: 240, Max:     None.
                                  are conceptually        3,000.             1,200.
                                  similar and
                                  equivalent to census
                                  block groups defined
                                  within the standard
                                  state-county-tract-
                                  block group
                                  geographic hierarchy
                                  used for tabulating
                                  and publishing
                                  statistical data.
Special use block groups.......  A block group, usually  None (or very      None (or very      At least
                                  coextensive with a      little) or         little) or         comparable in
                                  special census tract,   within the         within the         size to
                                  encompassing an         standard block     standard block     surrounding
                                  employment center,      group thresholds.  group thresholds.  standard block
                                  large airport, public                                         groups.
                                  park, public forest,
                                  or large water body
                                  with no (or very
                                  little) population or
                                  housing units.
----------------------------------------------------------------------------------------------------------------

C. Tribal Block Groups

    Tribal block groups 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 block 
groups allows for an unambiguous presentation of statistical 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 Indian tribal participant may define 
tribal block groups that cross county or state boundaries, or both. For 
federally recognized American Indian tribes with AIRs and/or ORTLs that 
have fewer than 1,200 residents, the Census Bureau will define one 
tribal census tract and one tribal block group coextensive with the AIR 
and/or ORTL. Tribal block groups must be delineated to meet all other 
census block group criteria, and must be identified uniquely so as to 
clearly distinguish them from county-based block groups. The Census 
Bureau will address the type of identifiers required for tribal block 
groups in more detail in a separate Federal Register notice pertaining 
to all American Indian areas, including statistical areas defined

[[Page 56298]]

through PSAP. Tribal block group boundaries will be held as census 
block boundaries. Census blocks, however, will be numbered uniquely 
within county-based block groups, and thus there will not be a direct 
relationship between a tribal block group identifier and the census 
block numbers. Tribal block groups are conceptually similar and 
equivalent to census block groups defined within the standard state-
county-tract-block group 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 block group 
geography is maintained separately from standard, county-based block 
groups. This change was first introduced for the 2010 Census, creating 
standard block groups nationwide and maintaining tribal block groups as 
a completely separate set of geography from standard block groups for 
both geographic and data presentation purposes, and eliminates, in 
part, the reliability and availability data issues for the tribal block 
groups and the derived standard block groups that were present in 
Census 2000.\5\
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    \5\ For Census 2000, tribal block groups were defined for 
federally recognized AIRs and/or ORTLs, and standard block groups 
were identified by superimposing county and state boundaries onto 
the Census 2000 tribal block groups. For Census 2000 products in 
which data were presented by state and county, the standard state-
county-tract-block group hierarchy was maintained, even for 
territory contained within an AIR and/or ORTL. In such instances, 
the state-county portions of tribal block groups were identified as 
individual block groups, and these standard block groups may not 
have met the minimum population or housing unit thresholds, 
potentially limiting sample data reliability or availability for 
both the tribal block groups and the derived standard block groups.
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    As with standard block groups submitted through this program, the 
tribal block groups are submitted to the Census Bureau, and are subject 
to review to ensure compliance with the published criteria. Detailed 
criteria pertaining to tribal block groups will be published in a 
separate Federal Register notice pertaining to all American Indian 
areas, including statistical areas defined through 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.
    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 
and in imagery 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/block group--Type of census tract or block 
group 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/block group. If 
delineated in a densely populated, urban area, a special use census 
tract/block group must have an area of at least one square mile. If 
delineated completely outside an urban area, a special use census 
tract/block group must have an area of at least 10 square miles.
    Statistical geographic entity--A geographic entity that is 
specially defined and delineated, such as block group, CDP, or census 
tract, so that the Census Bureau may tabulate data for it. Designation 
as a statistical entity neither conveys nor confers legal ownership, 
entitlement, or jurisdictional authority.
    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: November 1, 2018.
Ron S. Jarmin,
Deputy Director, Performing the Non-Exclusive Functions and Duties of 
the Director, Bureau of the Census.
[FR Doc. 2018-24570 Filed 11-9-18; 8:45 am]
 BILLING CODE 3510-07-P