Census Block Group Program for the 2010 Decennial Census; Final Criteria
Federal Register: March 14, 2008 (Volume 73, Number 51)
Notices
Page 13829-13836
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
DOCID:fr14mr08-32
DEPARTMENT OF COMMERCE
Bureau of the Census
Docket Number 070126022-8027-02
Census Block Group Program for the 2010 Decennial Census--Final
Criteria
AGENCY: Bureau of the Census, Commerce.
ACTION: Notice of final criteria and program implementation.
SUMMARY: Block groups are statistical geographic divisions of a census tract, defined for the tabulation and presentation of decennial census data. Block groups also will be used to tabulate and present period estimates from the American Community Survey (ACS) \1\ after 2010.
Block groups provide the geographic framework within which the Bureau of the Census (Census Bureau) defines census blocks. Each block group comprises a reasonably compact and contiguous cluster of census blocks; up to nine block groups can be contained within a single census tract.
\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 both the survey that is conducted in the
United States and in Puerto Rico.
This Notice announces the Census Bureau's final criteria for the
Census Block Group 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 17337), as well as the Census Bureau's response to these comments. In response to comments received, the Census Bureau has modified its proposed criteria for the Census Block Group Program for the 2010 Decennial
Census. Most provisions of the block group criteria for the 2010 Census remain unchanged from those used in conjunction with the 2000 Decennial
Census, except as follows. First, the same population and housing unit thresholds, a minimum of 600 people or 240 housing units and a maximum of 3,000 people or 1,200 housing units, will apply to all types of populated block groups, including block groups delineated within
American Indian reservations and off-reservation trust lands, the
Island Areas, and encompassing group quarters, military installations, and institutions. Second, housing unit counts may be used instead of population counts in the delineation of block groups. Third, the delineation of special land use tracts will be permitted, and encouraged, for areas with special land uses (e.g., airports, military reservations, public forests, public parks, and special places/group quarters) with an official name. Finally, a geographic framework of tribal block groups, separate from the standard block groups defined within counties, will be defined within federally recognized American
Indian reservations and/or off-reservation trust lands, subject to other population, housing, and boundary criteria contained in this document.
Upon publication of the final criteria contained in this Notice, the Census Bureau will offer governments, organizations, and interested data users 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 PSAP also encompasses the review and update of census tracts, 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:
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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
Page 13830
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 Census 2000, 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 block groups without regard to state and/or county boundaries, provided the tribe had a 1990 Census population of at least 1,000.
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Summary of Comments Received in Response to Proposed Criteria for the Census Block Group Program for the 2010 Census
The April 6, 2007, Federal Register (72 FR 17337) requested comment on the proposed criteria for delineating block groups for the 2010
Decennial Census which contained the following changes to the criteria used in the 2000 Decennial Census: (1) Increasing the minimum population and housing unit thresholds for block groups from 600 to 1,200 persons; (2) using housing unit counts (as an alternative to population counts) in the delineation review and update of block groups; (3) applying the same population and housing unit thresholds to all types of populated block groups in the United States,\2\ including block groups delineated on American Indian reservations and/or off- reservation trust lands,\3\ the Island Areas,\4\ and encompassing group quarters, military installations, and institutions; (4) allowing the delineation of block groups for large water bodies with areas of approximately 100 square miles or more, and special land uses (e.g., large airports or public parks) with an official name; and (5) allowing for geographic frameworks of tribal block groups (separate from the standard block groups defined within counties and standard census tracts) to be defined within federally recognized American Indian reservations and/or off-reservation trust lands.
\2\ For Census Bureau purposes, the United States includes the fifty states and the District of Columbia.
\3\ 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 and, if these areas have a population of 1,200 or greater, may delineate tribal tracts and tribal block groups for their reservation and off-reservation trust land.
\4\ 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 letters (each containing comments on several issues) from 33 organizations and individuals on the proposed minimum population and housing unit thresholds in the review and update of block groups, the proposed use of housing unit counts in the review and update of block groups, and the permitted delineation of census tracts for large water bodies and special land use tracts for which a single coextensive block group would be delineated. Comments received are summarized below, as well as the Census Bureau's response to these comments. 1. Minimum population and housing unit count thresholds in the review and update of block groups.
The Census Bureau received 32 comments opposed to increasing the minimum population threshold for block groups from 600 to 1,200. Only one commenter favored the proposed increase citing the need to maintain statistical reliability. Nearly all commenters expressed strong concern about the resulting loss of geographic detail and the detrimental impact on demographic analysis for small geographic areas should the minimum population be increased to 1,200. Commenters opposed to an increased minimum threshold included metropolitan planning organizations, councils of governments, local governmental agencies, private sector data users, a state redistricting liaison, and members of the Census Advisory Committee Professional Associations.
Additional research by the Census Bureau indicated that coefficients of variation for selected demographic characteristics did not improve substantially for block groups of 1,200 people compared to block groups of 600 people. Given the comments opposed to the proposed increased threshold, and taking into consideration the loss of geographic detail without substantive improvement to data quality and reliability, the Census Bureau will not change the minimum population threshold for block groups. The minimum block group threshold will remain at 600 people (240 housing units) for the 2010 Census.
Participants reviewing and delineating block groups for the 2010 Census and data users utilizing the sample-based data for block groups must be aware of the sample data reliability issues for geographies with low populations and the appropriate uses for sample data for low population geographies. The Census Bureau will provide additional information about sample data reliability and appropriate uses of sample data for geographic areas with low populations in the PSAP guidelines. 2. Using housing unit counts in the review and update of block groups.
The Census Bureau received five comments in response to the proposed use of housing unit counts in the review and update of block groups as an alternative to population counts where appropriate. Four commenters supported the concept. Another supported the proposal, but requested more guidance on when housing units, instead of population, should be used to define block groups. 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. 3. Permitting the delineation of census tracts, with coextensive block groups, for large water bodies and special land uses.
The Census Bureau received five comments in response to the proposed special land use tract and block group proposal. Four commenters representing various levels of local government, as well as nongovernmental organizations supported the concept. One commenter suggested that more discussion on the concept is needed to make an informed decision. Given the support of the special land use tract and coextensive block group designation, the Census Bureau will retain the concept in the final criteria for the 2010 Census.
The Census Bureau received three comments in response to the proposed large water body tract and block group proposal. Two commenters supported the concept. One commenter opposed the concept, citing increased confusion and disorientation for data users with respect to what is commonly depicted on non-census maps. Based on this
Page 13831
comment and after additional internal review, the Census Bureau has determined not to retain the large water block group concept in the final criteria for the 2010 Census.
Changes to the Proposed Criteria as a Result of Public Comments
Changes made to the final criteria (from the proposed criteria) in
``Section III, General Principles and Criteria for Block Groups for the 2010 Census'' are as follows: 1. Section A, ``General Principles,'' subsection 3: renumbered in this notice as subsection 2. We moved this section to emphasize that block groups form the geographic framework within which the Census
Bureau defines census blocks. 2. Section A, ``General Principles,'' subsection 2: renumbered in this notice as subsection 3. The first sentence in this subsection has been reworded to provide greater specificity and clarity. We added the third sentence pertaining to the Census Bureau's disclosure rules; this sentence had appeared in Section B.1 of the previous notice. In the fourth sentence, we 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. We also added sentences that clarify the minimum population and housing unit thresholds, noting that any block group with a population or housing unit count less than the minimum threshold should be updated, and clarifying that the Census Bureau will use Census 2000 population and housing unit counts to assess whether each block group submitted meets the minimum threshold criterion. 3. Section A, ``General Principles:'' added subsection 4, which notes that housing unit counts may be used in the review and updating of block groups, particularly with regard to communities that may not have sufficient residential population present on the date of the decennial census, but will have larger populations at other times of the year and for which estimates may be reflected in the ACS. 4. Section A, ``General Principles,'' subsection 4: renumbered in this notice as section 5. This subsection was moved because the new subsection 4 (see above) is closely related to issues discussed in subsection 3. We removed the reference to water body block groups since this proposed criterion has not been adopted in the final criteria. 5. Section B, ``Changes to the Block Group Criteria for the 2010
Census:'' this section was omitted from this notice as all changes are addressed in the final criteria. 6. Section C, ``Block Group Criteria for the 2010 Census,'' subsection 1: Renumbered in this notice as subsection 3. We revised the order of the first few criteria for clarity. Section C in the April 6, 2007 Federal Register (72 FR 17337) is now Section B in this Notice. 7. Section C, ``Block Group Criteria for the 2010 Census,'' subsection 2: Renumbered in this notice as subsection 1, for clarity.
We also changed the population threshold referenced in the subsection from 1,200 to 600, to reflect the decision to retain the latter as the minimum population threshold for a block group. 8. Section C, ``Block Group Criteria for the 2010 Census,'' subsection 3: Renumbered in this notice as subsection 2, reflecting the decision to revise the order of the first few criteria listed. Removed the last sentence relating to water body block groups since this proposed criterion has not been adopted in the final criteria. 9. Section C, ``Block Group Criteria for the 2010 Census,'' subsection 4: The second sentence was moved to the third sentence in this notice and the word ``permits'' was changed to ``requires'' to clarify that state and county boundaries must form block group boundaries. 10. Section C, ``Block Group Criteria for the 2010 Census,'' subsection 5: Added the word ``measurement'' after ``area'' in both the text and the tables in this subsection. In addition, in subsection 5.c, all text relating to water body block groups was removed since this proposed criterion has not been adopted in the final criteria. 11. Section D, ``Tribal Block Groups:'' We revised wording throughout the section to provide greater clarity. Discussion of tribal block groups is contained in Section C of this Notice.
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General Principles and Criteria for Block Groups for the 2010
Census
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General Principles 1. Block groups are statistical geographic divisions of a census tract, defined by the Census Bureau in cooperation with local officials and organizations, for the tabulation and dissemination of decennial census data, as well as period estimates of demographic and housing characteristics from the ACS. 2. Block groups form the geographic framework within which the
Census Bureau defines census blocks for use in tabulating and presenting decennial census data. Census blocks are numbered within block groups. 3. 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
(i.e., the sample data for smaller population geographies will likely be less reliable than the sample data for geographies with larger population). 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 block groups that fall between the minimum and maximum thresholds will improve the reliability and availability of data, and PSAP participants should consider these factors when defining their block groups.
Therefore, each block group must encompass at least 600 people or at least 240 housing units unless it is coextensive with a flagged special land use tract, or is coextensive with a county with fewer than 600 people. Any block group with a population or housing unit count less than the minimum threshold should be updated to meet or exceed the minimum threshold. The Census Bureau will use Census 2000 population and housing unit counts, with allowance made for growth since 2000, to assess whether each submitted block group meets this criterion. Program participants may submit local estimates as a surrogate for the Census 2000 population and housing unit counts for a block group. 4. 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 block group criteria. To accommodate this change, either population or housing units may be used in the review of block groups. 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 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 only represented as of the April 1 census day. 5. 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 block groups for analytical or
Page 13832
cartographic purposes or both. Such areas may be designated as special land use block groups to distinguish them from populated block groups.
Special land use block groups 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 block group. If located in a densely populated urban area, a special land use block group must have an area measurement of approximately one square mile or more. If delineated completely outside an urban area, a special land use block group 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 block groups and therefore will accept such areas as block groups even if some residential population is present.
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Block Group Criteria for the 2010 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 block groups that do not meet these final 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 the final tabulation geography is set for the 2010 Census.
The Census Bureau sets forth the following criteria for use in delineating 2010 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 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, or as coextensive with a special land use tract. 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 county. 3. A block group must comprise a reasonable compact, 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 visible and identifiable features. The use of visible features makes it easier to locate and identify block group boundaries over time as the locations of many visible features in the landscape tend to change infrequently.
The Census Bureau also requires the use of state and county boundaries in all states, and 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 block group boundaries for the 2010 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. 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 block group boundaries.
Table 1.--Acceptable MCD and Incorporated Place Boundaries
Boundaries of
MCDs not coincident with
All
Only conjoint
All MCD
the boundaries incorporated
incorporated
Boundaries
boundaries of incorporated
place
place places that
boundaries
boundaries themselves are
MCDs
Alabama..................................... ............... ............... ...............
X
Alaska...................................... ............... ............... ...............
X
Arizona..................................... ............... ............... ...............
X
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
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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 are permitted as block group 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 block group boundaries, the Census Bureau may, at its discretion, approve other nonstandard visible features, such as ridge lines, 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, glaciers, or the straight-line extensions of visible features and other lines-of-sight. 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).
Table 2.--Block Group Thresholds
Block group type
Threshold type
Minimum
Maximum
Standard & tribal block groups...... Population threshold... 600..................... 3,000.
Housing Unit threshold. 240..................... 1,200.
Special land use block groups....... Area measurement
1.0..................... none. threshold within an urban area (square miles).
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Area measurement
10...................... none. threshold outside an urban area (square miles).
Population thresholds..
(1) Little or none, or within standard block group thresholds.
The same population and housing unit thresholds apply to all types of populated block groups, including block groups delineated within
American Indian reservations and off-reservation trust lands, the
Island Areas, and encompassing group quarters, military installations, and institutions. This should improve the availability and reliability of data for block groups that had a lower threshold for the 2000
Decennial Census, and will create a single national standard. a. Census 2000 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 no or low 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
Census 2000. 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 2010 Census, the Census Bureau will allow the delineation of special land use census tracts, and special land use block groups will be created coextensive with these special land use tracts. A special land use tract, and hence a special land use block group, 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 or meet population or housing unit thresholds, and must not create a noncontiguous tract/block group. In some instances, multiple areas can be combined to form a single special land use tract/block group if the land management characteristics are similar, such as a special land use tract/block group comprising adjacent federal and state parks. If the special land use tract/block group is delineated in a densely populated, urban area, the tract/block group must have an area of approximately one square mile or more. If the special land use tract/block group is delineated completely outside an urban area, the tract/block group must have an area of approximately 10 square miles or more. 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 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. Block group numbers must always be unique within a census tract. 7. Block Group Types
Table 3 below contains a summary of the types of block groups (with their respective population, housing unit and area measurement thresholds) that will be used for the 2010 Census.
Table 3.--Summary of Block Group Types
How distinct from standard block
Population
Housing unit
Area measurement groups
thresholds
thresholds
thresholds
Standard & tribal block groups.. Tribal block
Minimum: 600;
Minimum: 240;
none. groups are
Maximum: 3,000.
Maximum: 1,200. 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.
Special land use block groups... A block group
Little or none, or Little or none, or 1.0 square mile coextensive with within the
within the
within an urban a special land
standard block
standard block
area/10 square use tract,
group thresholds. group thresholds. miles outside an encompassing a
urban area. large airport, public park, or public forest with little or no population or housing units. In a densely populated, urban area, a special land use block group must be approximately 1.0 square mile in area or greater.
If delineated completely outside an urban area, a special land use block group must have an area of 10 square miles or greater.
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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 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 block groups allows for an unambiguous presentation of statistical data specific to a federally recognized reservation and/or off-reservation trust land 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 \5\
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may define tribal block groups that cross county or state boundaries, or both. 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 American Indian statistical areas. 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 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.
\5\ For federally recognized American Indian tribes with reservations and/or off-reservation trust lands that have more than 1,200 residents, the Census Bureau will offer the tribal government the opportunity to delineate tribal block groups 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 land that have fewer than 1,200 residents, the Census Bureau will define one tribal tract and one tribal block group coextensive with the American Indian reservation and/or off-reservation trust land.
In order to provide meaningful statistical geographic areas within the reservation and/or off-reservation trust land, as well as make meaningful and reliable data available for these areas and their populations, for the 2010 Census, tribal block group geography will be maintained separately from standard county-based block groups, 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 block groups were defined for federally recognized
American Indian reservations and/or off-reservation trust lands, 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 American Indian reservation and/or off-reservation trust land. 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 group and the derived standard block groups. The change 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 in both geographic and data presentation purposes, eliminates, in part, these data issues from Census 2000.
As with standard block groups submitted through the program, the tribal block groups would be submitted to the Census Bureau, and would be subject to review to ensure compliance with the final published criteria. Tribal block groups will be defined as part of a separate
Tribal Statistical Areas Program (TSAP) for the 2010 Census. Detailed criteria pertaining to tribal block groups will be published in a separate Federal Register notice pertaining to all American Indian statistical areas defined through the TSAP.
-
-
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)--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 the areas, when combined, form a single piece of territory.
Noncontiguous areas form disjoint pieces.
Group quarters (GQ)--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 GQs are usually not related to each other. GQs 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. 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, line-of-sight extension of a road.
Special land use block group--Block group delineated coextensive with, or covering the same area as, the special land use tract.
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 census 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 ten square miles or more.
TIGER--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 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
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transmission line or pipeline, river or 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. E8-5075 Filed 3-13-08; 8:45 am
BILLING CODE 3510-07-P
