[Federal Register: March 14, 2008 (Volume 73, Number 51)]
[Notices]
[Page 13836-13844]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr14mr08-33]
-----------------------------------------------------------------------
DEPARTMENT OF COMMERCE
Bureau of the Census
[Docket Number 070321065-7903-02]
Census Tract Program for the 2010 Decennial Census--Final
Criteria
AGENCY: Bureau of the Census, Commerce.
ACTION: Notice of Final Criteria and Program Implementation.
-----------------------------------------------------------------------
SUMMARY: 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. Census tracts will also be
used to tabulate and publish estimates from the American Community
Survey (ACS) \2\ after 2010. The primary goal of the census tract
program is to provide a set of nationally consistent small, statistical
geographic units, with stable boundaries, that facilitate analysis of
data across time.
---------------------------------------------------------------------------
\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; 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 (PRCS). 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.
---------------------------------------------------------------------------
This Notice announces the Bureau of the Census' (Census Bureau's)
final criteria for the Census Tract Program for the 2010 Decennial
Census. In addition, this Notice contains a summary of comments
received to proposed criteria published in the April 6, 2007, Federal
Register (72 FR 17329), as well as the Census Bureau's response to
those comments. In response to comments received, the Census Bureau has
modified its proposed criteria for the Census Tract Program for the
2010 Decennial Census.
Upon publication of the final census tract criteria contained in
this Notice, the Census Bureau will offer governments, organizations,
and interested data users the opportunity to review and, if necessary,
suggest updates to the boundaries and attributes (e.g., tract code) of
the census tracts in their geographic area as part of the Participant
Statistical Areas Program (PSAP). In addition, to census tracts, the
PSAP also encompasses the review and update of block groups, census
designated places, and census county divisions (in selected states).
DATES: This notice's final criteria will be effective on March 14,
2008.
FOR FURTHER INFORMATION CONTACT: The Geographic Standards and Criteria
Branch, Geography Division, U.S. Census Bureau, via e-mail at
geo.psap.list@census.gov or telephone at (301) 763-3056.
SUPPLEMENTARY INFORMATION:
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 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; that is, to assure comparability and data
reliability through the standardization of the population thresholds
for census tracts, as well as requiring that their 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 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.
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.
II. Summary of Comments Received in Response to the Proposed Criteria
for the Census Tract Program for the 2010 Decennial Census
The April 6, 2007, Federal Register (72 FR 17329) requested comment
on the proposed census tract criteria for the 2010 Decennial Census
which contained the following changes to the criteria used in the 2000
Decennial Census: (1)
[[Page 13837]]
Lowering the minimum population threshold for most census tracts from
1,500 to 1,200; (2) using housing unit counts (as an alternative to
population counts) in the review and update of tracts; (3) applying the
same population and housing unit thresholds to all types of populated
tracts within the United States,\3\ including census tracts delineated
on American Indian reservations and off-reservation trust lands,\4\
Puerto Rico, the Island Areas,\5\ and encompassing group quarters,
military installations, and institutions. For census tracts delineated
in these areas, the 1,200 person threshold represents an increase from
the Census 2000 threshold of 1,000 people. The minimum housing unit
threshold for all census tracts would be 480. The maximum population
threshold of 8,000 persons/3,200 housing units and the optimum of 4,000
persons/1,600 housing units also will apply to all types of populated
census tracts; (4) allowing the delineation of census tracts for large
water bodies with areas of approximately 100 square miles or more and
special land use (e.g., large airports or public parks) with an
official name; and (5) allowing for geographic frameworks of tribal
tracts (separate from the standard census tracts defined within
counties) to be defined within federally recognized American Indian
reservations and off-reservation trust lands.
---------------------------------------------------------------------------
\3\ For Census Bureau purposes, the United States includes the
fifty States and the District of Columbia.
\4\ The proposed criteria for the tribal statistical areas
program will be outlined in a separate Federal Register notice. In
the tribal statistical areas program, federally recognized American
Indian tribes that have a reservation and/or off-reservation trust
land may delineate census designated places (CDPs), and, if these
areas have a population of 2,400 or greater, may delineate tribal
tracts and tribal block groups for their reservation and off-
reservation trust land.
\5\ For Census Bureau purposes, the Island Areas includes
American Samoa, the Commonwealth of the Northern Mariana Islands,
Guam, the U.S. Virgin Islands, and the U.S. Minor Outlying Islands.
The U.S. Minor Outlying Islands is 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.
---------------------------------------------------------------------------
The Census Bureau received comments from 11 individuals regarding
the proposed use of housing unit counts in the review and update of
census tracts, the permitted delineation of census tracts for large
water bodies and special land uses, and the proposed tribal tract
approach. Commenters represented a variety of agencies and
organizations, including state and local government agencies, non-
profit policy research and analysis organizations, non-governmental
organizations, professional societies, and private sector companies.
Comments received by the Census Bureau are summarized below, as well as
the Census Bureau's response to these comments.
1. Using Housing Unit Counts in the Review and Update of Tracts
The Census Bureau received five comments in response to the
proposed use of housing unit counts in the review and update of tracts
and block groups as an alternative to population counts where
appropriate. All five comments supported the concept, although one
commenter requested more guidance on when housing units should be used
to define tracts instead of population. Given the support of using
housing unit counts in the review and update for census tracts, the
Census Bureau will retain the concept in the final criteria for the
2010 Census. Guidance as to when housing unit counts should be used in
place of population counts in the review and update of census tracts
will be discussed in this notice, and further detailed in the PSAP
guidelines.
2. Permitting the Delineation of Census Tracts for Large Water Bodies
and Special Land Uses
The Census Bureau received four comments in response to the
proposal to encourage delineation of special land use tracts. Three
commenters supported the concept. One commenter neither supported nor
opposed the concept, but stated that more discussion about the concept
is required. Given the support of the special land use tract
designation, the Census Bureau will retain the concept in the final
criteria for the 2010 Decennial Census.
Three comments were received in response to the proposal to
encourage delineation of large water body tracts. Two commenters
supported the concept. One commenter opposed the concept, citing
increased confusion and disorientation for data users with respect to
what is commonly seen on non-census maps. Additional internal review
and discussion of the large water body tract proposal led to a
recommendation to not retain this requirement in the final criteria.
Given the mixed response to the large water tract proposal, and
subsequent internal review and discussion, the Census Bureau will not
retain the large water tract concept in the final criteria for the 2010
Decennial Census.
3. Allowing for a Geographic Framework of Tribal Census Tracts Defined
Within Federally Recognized American Indian Reservations and Off-
Reservation Trust Lands, and Separate From the Standard Census Tracts
Defined Within Counties
The Census Bureau received two comments supporting the proposed
tribal tract approach. In addition, two commenters requested
clarification of the concept. The tribal tract approach will be fully
explained in the ``American Indian Areas (AIAs) for the 2010 Census--
Proposed Criteria and Guidelines'' Federal Register notice to be
published.
Changes to Proposed Criteria for the Census Tract Program for the 2010
Decennial Census
Changes made to the final criteria (from the proposed criteria) in
``Section III, General Principles and Criteria for Census Tracts for
the 2010 Census'' are as follows:
1. Section A, ``General Principles,'' subsection 2, fourth
sentence: replaced ``local governments and planners'' with ``PSAP
participants'' because not all participants in the 2010 PSAP will be
representatives of local governments or will be professional planners.
In the fifth sentence, we deleted the reference to water body tracts
since this proposed criterion has not been adopted in the final
criteria. We also changed the wording in the fifth sentence to improve
the flow of the text and provide greater clarity.
2. Section A, ``General Principles,'' subsection 2: added sentences
referencing optimal population and housing unit thresholds for census
tracts and the importance of the optimum threshold with regard to
reliability and availability of sample-based data.
3. Section A, ``General Principles,'' subsection 3: added text to
help clarify why we are now permitting the use of housing unit counts
in the review and updating of census tracts for the 2010 Census.
4. Section A, ``General Principles,'' subsection 4: removed the
reference to water body tracts since this proposed criterion has not
been adopted in the final criteria.
5. Section B, ``Changes to the Census Tract Criteria for the 2010
Census:'' this section was omitted from this Notice as all changes are
addressed in the final criteria.
6. Section C, ``Census Tract Criteria for the 2010 Census:'' moved
the following criterion ``Census tracts must not cross State and county
boundaries,'' as the first listed criterion. Because this criterion
supersedes all other criteria, we felt it required specific mention.
[[Page 13838]]
7. Section C in the April 6, 2007 Federal Register (72 FR 17329) is
now Section B.
8. Section C, ``Census Tract Criteria for the 2010 Census:'' the
criterion listed first, ``A census tract must comprise a reasonably
compact and contiguous land area,'' is now listed third in this notice,
partly as a result of the addition of the criterion relating to
adherence to state and county boundaries, but also to produce a more
logical flow to the criteria. As a result of this change, and the
change listed above, all other criteria in this section have been
renumbered.
9. Section C, ``Census Tract Criteria for the 2010 Census,''
subsection 4.g: removed reference to water body tracts since that
proposed criterion has been eliminated from the final criteria.
10. Section C, ``Census Tract Criteria for the 2010 Census,''
subsection 5: added the word ``measurement'' after ``area'' in the
title of the subsection, in the text, and in the table providing tract
thresholds. In subsection 5a, we revised the wording to improve flow
and provide greater clarity.
11. Section C, ``Census Tract Criteria for the 2010 Census,''
subsection 5c: we revised the text in this subsection to provide
greater clarity. We removed the reference to the level of population or
housing units at which a tract need not be merged since this is not a
specific criterion. The Census Bureau will provide a variety of
examples in the PSAP guidelines to help guide participants when
deciding whether to merge adjacent tracts.
12. Section C, ``Census Tract Criteria for the 2010 Census,''
subsections 5d and 5e: we changed the order in which these subsections
appear in the final criteria to provide a more logical flow to the
presentation. In addition, we deleted the reference to water body
tracts that appeared in subsection 5e of the proposed criteria.
13. Section C, ``Census Tract Criteria for the 2010 Census,''
subsection 6b: removed criteria pertaining to codes for water body
tracts since water body tracts have been deleted from the final
criteria, and modified the high end of the range of allowable census
tract identifiers from 9949 to 9989.
14. Section C, ``Census Tract Criteria for the 2010 Census,''
subsection 7: added the word ``measurement'' after ``area'' in the text
and table in this section.
15. Section D, ``Tribal Tracts:'' in response to comments received,
we revised wording throughout the section to provide greater clarity.
Discussion of tribal tracts is contained in Section C of this Notice.
III. General Principles and Criteria for Census Tracts for the 2010
Decennial Census
A. General Principles
1. A century of census tract use has shown that continuity and
comparability in tracts and their boundaries over time are of
considerable importance to data users. Comparability has always been a
goal in the census tract program since its inception for the 1910
census; however, as the use of tract data increases, the importance of
comparability increases as well. Maintaining comparability of tract
boundaries over time facilitates longitudinal data analysis. The advent
of the ACS and the averaging of sample data for tracts over a five-year
span further underscore the need for consistent tract boundaries over
time.
Pursuant to this goal of continuity and comparability, 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. The sample size for the ACS is smaller than the sample from the
decennial census long form of previous censuses. As a general rule,
estimates from programs providing sample data, including the ACS, for
geographic areas with smaller populations will be subject to higher
variances than comparable estimates for areas with larger populations.
In addition, the Census Bureau's disclosure rules may have the effect
of restricting the availability and amount of sample data published for
geographic areas with small populations. Aiming to create census tracts
that meet the optimal population of 4,000 and maintaining minimum
thresholds will improve the reliability and availability of data, and
PSAP participants should consider these factors when defining their
census tracts. Therefore, each census tract must encompass at least
1,200 people or at least 480 housing units unless it is flagged as a
special land use tract, or is coextensive with a county with fewer than
1,200 people. 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 1). Optimally, census tracts should
have 4,000 people or 1,600 housing units. Meeting or exceeding the
optimum thresholds will help improve the reliability of sample data for
census tracts. The Census Bureau will use Census 2000 population and
housing unit counts, with allowance made for growth since 2000, to
assess whether each census tract submitted meets this criterion.
Program participants may submit local estimates as a surrogate for the
Census 2000 population and housing unit counts for a census tract.
[[Page 13839]]
[GRAPHIC] [TIFF OMITTED] TN14MR08.074
3. With the advent of the ACS and the ``continuous measurement'' of
characteristics of the population and housing based on a five-year
average, there are some new issues to consider in the census tract
criteria. To accommodate this change, either population or housing
units may be used in the review of census tracts. The use of housing
unit counts accommodates 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 period 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); whereas, in the past
local area data were represented as of the April 1 census day.
4. The Census Bureau recognizes that there are geographic areas
that are not characterized by a residential population, and which local
participants may wish to separate from populated tracts for analytical
or cartographic purposes or both. Such areas may be designated as
special land use tracts to distinguish them from populated census
tracts. Special land use tracts must be designated as a specific type
of land use (e.g., state park, municipal park) and have an official
name, generally have little or no residential population or housing
units, and must not create a noncontiguous census tract. If located in
a densely populated urban area, a special land use tract must have an
area measurement of approximately 1 square mile or more. If delineated
completely outside an urban area, a special land use tract must have an
area of approximately 10 square miles or more. The Census Bureau
recognizes that some special land use areas not intended for
residential population, such as parks, may contain some population,
such as caretakers or the homeless. Our intent is to allow for the
delineation of parks and other special land use areas as separate
tracts and therefore will accept such areas as tracts even if some
residential population is present.
5. 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 and off-
reservation trust lands. Each contiguous American Indian reservation
and/or off-reservation trust land should be included, along with any
necessary territory outside the reservation and/or off-reservation
trust land, within a single census tract or as few census tracts as
possible for the 2010 Census. This is the only situation in which
retracting is encouraged. For example, see Figure 2 below.
[[Page 13840]]
[GRAPHIC] [TIFF OMITTED] TN14MR08.075
B. Census Tract Criteria for the 2010 Decennial Census
The criteria herein apply to the United States, including federally
recognized American Indian reservations and off-reservation trust
lands, Puerto Rico, and the Island Areas. The Census Bureau may modify
and, if necessary, reject any proposals for census tracts that do not
meet these final criteria. In addition, the Census Bureau reserves the
right to modify the boundaries and attributes of tracts as needed to
meet the published criteria and/or maintain geographic relationships
before the final tabulation geography is set for the 2010 Census.
The Census Bureau Sets Forth the Following Criteria for Use in
Reviewing, Updating, and Delineating 2010 Census Tracts:
1. Census tracts must not cross state or county boundaries.
2. A census tract must cover the entire land and water area of a
county.
3. A census tract must comprise a reasonably compact and contiguous
land area.
Noncontiguous boundaries are permitted only where a noncontiguous
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 included within an adjacent
or proximate tract. For example, an island that does not meet the
minimum population threshold for recognition as a separate tract should
be combined with other proximate land to form a single tract. Each case
will be reviewed and accepted at the Census Bureau's discretion.
4. 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 visible and
identifiable features. The use of visible features also makes it easier
to locate and identify tract boundaries over time, as the locations of
many visible features in the landscape tend to change infrequently.
State and county boundaries must be census tract boundaries. The Census
Bureau also permits the use of incorporated place and minor civil
division 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 2010 Census:
a. State and county boundaries must always be census tract
boundaries. This criterion takes precedence over all other criteria or
requirements (except for tribal tracts on federally recognized American
Indian reservations and/or off-reservation trust lands).
b. American Indian reservation and off-reservation trust land
boundaries.
c. Visible, perennial natural and cultural 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 minor civil division (MCD) and
incorporated place boundaries may be used as census tract boundaries.
Table 1.--Acceptable MCD and Incorporated Place Boundaries
----------------------------------------------------------------------------------------------------------------
Boundaries of MCDs
not coincident
with the
All MCD boundaries of All incorporated Only conjoint
boundaries incorporated place boundaries incorporated
places that places boundaries
themselves are
MCDs
----------------------------------------------------------------------------------------------------------------
Alabama......................... .................. .................. .................. X
Alaska.......................... .................. .................. .................. X
Arizona......................... .................. .................. .................. X
[[Page 13841]]
Arkansas........................ .................. .................. .................. X
California...................... .................. .................. .................. X
Colorado........................ .................. .................. .................. X
Connecticut..................... X .................. X ..................
Delaware........................ .................. .................. .................. X
Florida......................... .................. .................. .................. X
Georgia......................... .................. .................. .................. X
Hawaii.......................... .................. .................. .................. X
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
----------------------------------------------------------------------------------------------------------------
\a\ Townships only.
\b\ Governmental townships only.
e. Additionally, the following legally defined, administrative
boundaries would be permitted as census tract boundaries:
i. Barrio, barrio-pueblo, and subbarrio boundaries in Puerto Rico;
ii. Census subdistrict 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 2010 Census
activities.
f. When acceptable visible and governmental boundary features are
not available for use as tract boundaries, the Census Bureau may, at
its discretion, approve other nonstandard visible features, such as
ridgelines, above-ground pipelines, intermittent streams, or fence
lines. The Census Bureau may also accept, on a case-by-case basis, the
boundaries of selected nonstandard and potentially nonvisible features,
such as the boundaries of military installations, national parks,
national monuments, national forests, other types of parks or forests,
airports, marine ports, cemeteries, golf courses, penitentiaries/
prisons, or glaciers, or the straight-line
[[Page 13842]]
extensions of visible features and other lines-of-sight.
g. The boundaries of parks, forests, large airports, and military
installations, provided the boundaries are clearly marked or easily
recognized.
5. 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).
Table 2.--Tract Thresholds
----------------------------------------------------------------------------------------------------------------
Tract type Threshold type Optimum Minimum Maximum
----------------------------------------------------------------------------------------------------------------
Standard & tribal tracts............. Population threshold.... 4,000 1,200 8,000
--------------------------------------------------------------------------
Housing Unit threshold.. 1,600 480 3,200
----------------------------------------------------------------------------------------------------------------
Special land use tracts.............. Area measurement none 1.0 none
threshold for an urban
area (square miles).
--------------------------------------------------------------------------
Area measurement none 10 none
threshold outside an
urban area (square
miles).
--------------------------------------------------------------------------
Population threshold.... Little or none, or within the standard tract
thresholds
----------------------------------------------------------------------------------------------------------------
a. Population counts should be used, in most cases, to review and
update census tracts. Housing unit counts should be used for seasonal
communities that have no or low population on census day (April 1).
Locally produced population and housing unit estimates can be used when
reviewing and updating tracts, especially in areas that have
experienced considerable growth since Census 2000.
b. The housing unit thresholds are based on a national average of
2.5 persons per household. The Census Bureau recognizes that there are
regional variations to this average and will take this into
consideration when reviewing all tract proposals.
c. The Census Bureau recognizes the tension that exists between
meeting the optimum population or housing unit threshold in a tract and
maintaining tract comparability over time. For example, if sufficient
population or housing unit growth has occurred since 2000 or is
expected before 2010 for a census tract, based on Census 2000 data, was
below the minimum thresholds, the tract should not be merged with
another tract. Supporting evidence may be requested by the Census
Bureau. However, should the census tract's population not increase as
expected and does not meet either of the minimum thresholds in 2010,
this may adversely affect the reliability and availability of any
sample estimates for that tract. For this reason, the Census Bureau
suggests merging the census tract with another if there is a
possibility that anticipated growth will not be sufficient to meet
minimum thresholds.
d. For the 2010 Census, the Census Bureau allows the delineation of
special land use tracts. A special land use tract must be designated as
a specific land use type (e.g., State park), must have an official name
(e.g., Jay Cooke State Park), have little or no residential population,
and must not create a noncontiguous tract. In some instances, multiple
areas can be combined to form a single special land use tract if the
land management characteristics are similar, such as a special land use
tract comprising adjacent Federal and State parks. If the special land
use tract is delineated in a densely populated, urban area, the tract
must have an area of approximately one square mile or more. If the
special land use tract is delineated completely outside an urban area,
the tract must have an area of approximately 10 square miles or more.
e. The Census Bureau may waive the maximum population and housing
unit thresholds as required to achieve the objectives of this notice.
6. 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
2010 Census is from 1 to 9989 (but, see 6.c. below); 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
American Indian reservations and/or off-reservation trust lands can
continue to be numbered from 9400 to 9499. Local participants may opt
to renumber these census tracts in a numeric range consistent with the
rest of the county since tribal tracts will represent a separate and
distinct geographic framework.
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 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 Census 2000 is split, each portion
must be given a new suffix.
f. The range of acceptable census tract suffixes is .01 to .98.
7. 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 2010 Census.
[[Page 13843]]
Table 3.--Summary of Census Tract Types
----------------------------------------------------------------------------------------------------------------
How distinct from Population Housing unit Area measurement
standard census tracts thresholds thresholds thresholds
----------------------------------------------------------------------------------------------------------------
Standard & tribal tracts....... Tribal tracts are Optimum: 4,000; Optimum: 1,600; none.
conceptually similar Minimum: 1,200; Minimum: 480;
and equivalent to Maximum: 8,000. Maximum: 3,200.
census tracts defined
within the standard
state-county-tract-
block group
geographic hierarchy
used for tabulating
and publishing
statistical data.
Special land use tract......... A tract encompassing a Little or none... Little or none... 1.0 square mile
large airport, public within an urban
park, or public area/10 square
forest with little or miles outside an
no population or urban area.
housing units. In a
densely populated,
urban area, a special
land use tract should
be approximately 1
square mile in area
or greater. If
delineated completely
outside an urban
area, a special land
use tract should have
an area of 10 square
miles or greater.
----------------------------------------------------------------------------------------------------------------
C. Tribal Tracts
Tribal 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 American Indian
reservations and/or off-reservation trust lands. As such, they
recognize the unique statistical data needs of federally recognized
American Indian tribes. The delineation of tribal tracts allows for an
unambiguous presentation of tract-level data specific to the American
Indian reservation and/or off-reservation trust lands without the
imposition of state or county boundaries, which might artificially
separate American Indian populations located within a single
reservation and/or off-reservation trust land. To this end, the
American Indian tribal participant may define tribal tracts that cross
county or State boundaries, or both. For federally recognized American
Indian tribes with reservations and/or off-reservation trust lands that
have more than 2,400 residents, the Census Bureau will offer the tribal
government the opportunity to delineate tribal tracts and other tribal
statistical geography on their reservation and/or off-reservation trust
land. For federally recognized tribes with an American Indian
reservation and/or off-reservation trust lands that have fewer than
2,400 residents, the Census Bureau will define one tribal tract
coextensive with the reservation and/or off-reservation trust land.
Tribal tracts must be delineated to meet all other census tract
criteria, and must be numbered uniquely so as to clearly distinguish
them from county-based census tracts. Tribal 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.
Tribal tracts are defined to provide meaningful and reliable
statistical data, particularly sample-based data, for small geographic
areas within a reservation and/or off-reservation trust land. To
accomplish this in as meaningful a manner as possible, tribal tract
geography will constitute a geographic framework separate from standard
county-based census tracts and will be defined through a separate
program designed specifically for tribal statistical geography. This
differs from the procedure for Census 2000 in which tribal tracts were
defined for federally recognized American Indian reservations and/or
off-reservation trust lands 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 American Indian
reservation and/or off-reservation trust land. 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; therefore, potentially limiting sample
data reliability or availability for both the tribal tract and the
derived standard tracts. The change in the tribal tract program for the
2010 Census, creating standard, county-based census tracts nationwide
and maintaining tribal tracts as a completely separate set of geography
from standard tracts for both geographic information and data
presentation purposes, seeks to eliminate, in part, these issues that
existed with Census 2000 data.
As with standard census tracts submitted through this program, the
tribal tracts will be submitted to the Census Bureau, and will be
subject to review to ensure compliance with the final published
criteria. Tribal tracts will be defined as part of a separate Tribal
Statistical Areas Program (TSAP) for the 2010 Census. Detailed criteria
pertaining to tribal tracts will be published in a separate Federal
Register notice pertaining to all American Indian statistical areas
defined through the TSAP.
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--A federally recognized
American Indian land area located outside the boundaries of an American
Indian reservation whose boundaries are established by deed and over
which a federally recognized American Indian tribal government has
governmental authority.
American Indian reservation (AIR)--A federally recognized American
Indian land area 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 shared by two adjacent
geographic entities.
Contiguous--A description of areas sharing common boundaries, such
that
[[Page 13844]]
the areas, when combined, form a single piece of territory.
Noncontiguous areas form disjoint pieces.
Group quarters--A place 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 tract so
that comparability over time is not maintained.
Special land use tract--Type of census tract that must be
designated as a specific land use type (e.g., state park) and have an
official name (e.g., Jay Cooke State Park), must have little or no
residential population or housing units, and must not create a
noncontiguous tract. If delineated in a densely populated, urban area,
a special land use tract must have an area of approximately one square
mile or more. If delineated completely outside an urban area, a special
land use tract must have an area of approximately 10 square miles or
more.
TIGER[reg]--Topologically Integrated Geographic Encoding and
Referencing database developed by the Census Bureau to support its
mapping needs for the decennial census and other Census Bureau
programs. The topological structure of the TIGER[reg] database defines
the location and relationship of boundaries, streets, rivers,
railroads, and other features to each other and to the numerous
geographic areas for which the Census Bureau tabulates data from its
censuses and surveys.
Visible feature--A map feature that can be seen on the ground, 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.
Executive Order 12866
This notice has been determined to be not significant under
Executive Order 12866.
Paperwork Reduction Act
This program notice does not contain a collection of information
subject to the requirements of the Paperwork Reduction Act, 44 U.S.C.,
Chapter 35.
Dated: March 10, 2008.
Steve H. Murdock,
Director, Bureau of the Census.
[FR Doc. E8-5076 Filed 3-13-08; 8:45 am]
BILLING CODE 3510-07-P