Bureau of the Census, Commerce.
Notice of proposed program revisions and request for comments.
Census tracts are relatively permanent small-area geographic divisions of a county or statistically equivalent entity  defined for the tabulation of decennial census data and selected other statistical programs. Census tracts also will be used to tabulate and publish estimates from the American Community Survey (ACS)  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.
Most provisions of the census tract criteria for the 2010 Census remain unchanged from those used in conjunction with Census 2000. However, based on consultation with data users and internal review the Bureau of the Census (Census Bureau) is proposing the following changes for the 2010 Census: (1) Lowering the minimum population threshold for census tracts; (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, including census tracts delineated on American Indian reservations and off-reservation trust lands, Puerto Rico, the Island Areas, and encompassing group quarters, military installations, and institutions; (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.
In addition to proposed criteria, this notice includes a description of the changes from the criteria used for Census 2000 and a list of definitions of key terms used in the criteria.
The Census Bureau is publishing this notice in the Federal Register to request comments from the public and other government agencies. The Census Bureau will respond to the comments received as part of the publication of final criteria in the Federal Register. After the final criteria are published in the Federal Register, the Census Bureau will offer designated governments or organizations an opportunity to review and, if necessary, suggest updates to the boundaries and attributes (e.g., tract code) of the census tracts in their geographic area under the Participant Statistical Areas Program (PSAP). In addition to census tracts, the program also encompasses the review and update of block groups, census designated places, and census county divisions.
Written comments must be submitted on or before July 5, 2007.
Please direct all written comments on this proposed program to the Director, U.S. Census Bureau, Room 8H001, mail stop 0100, Washington, DC 20233-0001.Start Further Info
FOR FURTHER INFORMATION CONTACT:
Requests for additional information on this proposed program should be directed to Michael Ratcliffe, Chief, Geographic Standards and Criteria Branch, Geography Division, U.S. Census Bureau, via e-mail at firstname.lastname@example.org or telephone at 301-763-3056.End Further Info End Preamble Start Supplemental 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 Start Printed Page 17330twenty-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. General Principles and Criteria for Census Tracts for the 2010 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 local governments and planners should consider these factors when defining their census tracts. Therefore, the Census Bureau proposes that any census tracts not flagged as a water body or special land use tract (General Principle 4) must encompass at least 1,200 people or at least 480 housing units. 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). 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.Start Printed Page 17331
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. The Census Bureau proposes the use of either population or housing units in the review of census tracts. 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. The Census Bureau proposes identifying these areas as water body tracts and special land use 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 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/or 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. See, for example, Figure 2 below.Start Printed Page 17332
B. Changes to the Census Tract Criteria for the 2010 Census
Most provisions of the census tract criteria for the 2010 Census would remain unchanged from those used in conjunction with Census 2000 with only the following exceptions:
1. The minimum population threshold for census tracts would be 1,200, lowered from the minimum threshold of 1,500 used in Census 2000. This change seeks to create a standard minimum threshold for census block groups and census tracts, in order to support the reliability and availability of sample data for these statistical geographies.
2. Housing unit counts may be used instead of population counts in the review and update of tracts. This change seeks to accommodate 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.
3. For Census 2000, minimum population thresholds for census tracts varied. The minimum population threshold for census tracts delineated on American Indian reservations and off-reservation trust lands was 1,000. This differed from the minimum threshold of 1,500 people for census tracts defined elsewhere in the United States, as well as in Puerto Rico and the Island Areas. Optimum populations for census tracts also varied: 4,000 in the United States and Puerto Rico, and 2,500 on American Indian reservations and in the Island Areas. The maximum population for a census tract in any of these areas was 8,000. In addition, for Census 2000, tracts that enclosed an institution, a military installation, or other “special place” had a minimum population requirement of 1,000 inhabitants, with no optimum or maximum.
For the 2010 Census the same population and housing unit thresholds would apply to all types of populated tracts, including census tracts delineated on American Indian reservations and off-reservation trust lands, the Island Areas, and encompassing group quarters, military installations, and institutions. The Census Bureau proposes this change in order to aid in the availability and reliability of data for all tracts and to create a single national standard.
4. The delineation of census tracts would be permitted, and encouraged, for the following types of geographic areas:
a. Large water bodies with areas of approximately 100 square miles or more.
b. Special land uses (for example, large airports, public parks, or public forests) with an official name.
The Census Bureau would require that special land use tracts have little or no residential population. All such census tracts would meet all other tract criteria.
5. A geographic framework of tribal tracts, separate from the standard census tracts defined within counties, may 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. This represents a change from the practice for Census 2000. The Census Bureau proposes this change to better recognize the unique statistical data needs of federally recognized American Indian tribes and their reservation and off-reservation trust lands.
C. Census Tract Criteria for the 2010 Census
The criteria proposed 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 the established 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 proposes the following criteria for use in reviewing 2010 Census tracts:
1. 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 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 Start Printed Page 17333threshold 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.
2. A census tract must cover the entire land and water area of a county.
In counties containing coastal waters, territorial sea, and portions of the Great Lakes, and very large, contiguous, inland water bodies, a single water body tract should be created for each discrete water body to provide for complete census tract coverage.
3. 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 Census Bureau also permits the use of State and county boundaries in all States, and incorporated place and minor civil division boundaries in States where those boundaries tend to remain unchanged over time (see Table 1). 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.
The following features are preferred as census tract boundaries for the 2010 Census:
a. State and county boundaries must always be tract boundaries. This criterion takes precedence over all other criteria or requirements except for the population threshold criteria for tribal tracts on 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 tract boundaries.
|All MCD boundaries||Boundaries of MCDs not coincident with the boundaries of incorporated places that themselves are MCDs||All incorporated place boundaries||Only conjoint incorporated places boundaries|
|Start Printed Page 17334|
|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 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, or glaciers, or the straight-line extensions of visible features and other lines-of-sight.
g. The boundaries of large water bodies and special land use tracts, including parks, forests, large airports, and military installations, provided the boundaries are clearly marked or easily recognized.
4. Population, Housing Unit, and Area Thresholds
The Census Bureau proposes the following population, housing unit, and area threshold criteria for census tracts (as summarized in Table 2).
|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|
|Water body tracts||Area threshold (square miles)||none||100||none|
|Special land use tracts||Area threshold for an urban area (square miles)||none||1||none|
|Area threshold outside an urban area (square miles)||none||10||none|
a. Population counts should be used in tract review in most cases. 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 population growth has occurred since 2000 or is expected before 2010 for a census tract, the tract should not be merged if it has a Census 2000 population of at least 1,100 or a housing unit count of at least 440 and acceptable supporting evidence is supplied by the PSAP participant that population and/or housing unit growth has occurred since Census 2000, or will likely occur before 2010, and has been sufficient to meet the minimum thresholds. 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. Start Printed Page 17335
d. The Census Bureau may waive the maximum population and housing thresholds as required to achieve the objectives of this notice.
e. For the 2010 Census, the Census Bureau encourages the delineation of special-use tracts in specific types of areas.
i. 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.
ii. A water body tract must encompass all or part of a territorial sea, coastal water, a Great Lake, or an inland water body at least 100 square miles in area. If a water body meets this criterion and is in more than one county, each county can delineate a tract for its portion of the water body. Any islands within a qualifying water body should be included within a separate tract.
5. 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 9949 (but, see 5.c. below); tracts delineated specifically to complete coverage of large water bodies will be numbered from 9950 to 9989 in each county. All other tracts that fall within the 9950-9989 range must be renumbered. For Census 2000, water body tracts were all coded 0000. Each of these must be renumbered for the 2010 Census.
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 are proposed to be a separate and distinct geographic entity.
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.
6. Census Tract types
Table 3 below contains a summary of the types of census tracts (with their respective population, housing unit and area characteristics) that the Census Bureau proposes to use for the 2010 Census.
|How distinct from standard census tracts||Population thresholds||Housing unit thresholds||Area thresholds|
|Standard & tribal tracts||Tribal tracts are conceptually similar and equivalent to census tracts defined within the standard State-county-tract-block group geographic hierarchy used for tabulating and publishing statistical data||Optimum: 4,000; Minimum: 1,200; Maximum: 8,000||Optimum: 1,600; Minimum: 480; Maximum: 3,200||None.|
|Water body tract||A tract encompassing all or part of a territorial sea, coastal water, a Great Lake, or an inland water body at least 100 square miles in area||Zero||Zero||100 square miles if an inland water body.|
|Special land-use tract||A tract encompassing a 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 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||Little or none||Little or none||1 square mile within an urban area/10 square miles outside an urban area.|
D. 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 reservation 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 reservations 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 Start Printed Page 17336lands that have fewer than 2,400 residents, the Census Bureau will define one tribal tract and one tribal block group 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-block group geographic hierarchy used for tabulating and publishing statistical data.
In order to provide meaningful statistical geographic areas within the reservation and/or off-reservation trust land as well as to make meaningful and reliable data available for these areas and their populations, the Census Bureau proposes that for the 2010 Census, standard census tracts be delineated nationwide, and the tribal tract geography be maintained separately and 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 or housing unit thresholds, therefore potentially limiting sample data reliability or availability for both the tribal tract and the derived standard tracts. The proposed 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 would be submitted to the Census Bureau, and would 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.
III. 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) 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.
Coastal water—Water bodies between territorial seas and inland water, the encompassing headlands being more than one mile apart and less than 24 miles apart.
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.
Great Lakes' waters—Water area beyond one mile wide headland embayments located in any of the five Great Lakes: Erie, Huron, Michigan, Ontario, or Superior.
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.
Inland water—Water bodies entirely surrounded by land or at the point where their opening to coastal waters, territorial seas, or the Great Lakes is less than one mile across.
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.
Territorial seas—Water bodies not included under the rules for inland water, coastal water, or Great Lakes' waters, see above.
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 Start Printed Page 17337numerous 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.
Water body tract—Type of tract encompassing territorial seas, coastal water, the Great Lakes, or inland water at least 100 square miles in area. If an inland water body meets this criterion, each county can delineate a tract for its portion of the water body.
Executive Order 12866
This notice has been determined to be not significant under Executive Order 12866.
Paperwork Reduction Act
This program notice does not represent a collection of information subject to the requirements of the Paperwork Reduction Act, 44 U.S.C. Chapter 35.Start Signature
Dated: April 3, 2007.
Charles Louis Kincannon,
Director, Bureau of the Census.
1. Includes parishes in Louisiana; boroughs, city and boroughs, census areas, and municipalities in Alaska; independent cities in Maryland, Missouri, Nevada, and Virginia; districts in American Samoa and 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.”Back to Citation
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.Back to Citation
3. For Census Bureau purposes, the United States includes the fifty States and the District of Columbia.Back to Citation
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.Back to Citation
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.Back to Citation
[FR Doc. E7-6466 Filed 4-5-07; 8:45 am]
BILLING CODE 3510-07-P