Bureau of the Census, Commerce.
Notice of final criteria and program implementation.
Census tracts are relatively permanent small-area geographic divisions of a county or statistically equivalent entity defined for the tabulation and presentation of data from the decennial census and selected other statistical programs. The Census Bureau is publishing this notice in the Federal Register to announce final criteria for defining census tracts for the 2020 Census. Census tracts defined by these criteria will also be used to tabulate and publish estimates from the American Community Survey (ACS) and potentially data from other Bureau of the Census (Census Bureau) censuses and surveys. In addition to census tracts, the Participant Statistical Areas Program (PSAP) encompasses the review and update of census block groups, census designated places, and census county divisions.
This notice's final criteria will be applicable on December 13, 2018.
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FOR FURTHER INFORMATION CONTACT:
Requests for additional information on this proposed program should be directed to Vincent Osier at the Geographic Standards, Criteria, and Quality Branch, Geography Division, U.S. Census Bureau, via email at email@example.com or telephone at 301-763-3056.
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Start Supplemental Information
Census tracts are relatively permanent small-area geographic divisions of a county or statistically equivalent entity 
defined for the tabulation and presentation of data from the decennial census and selected other statistical programs. The Census Bureau is publishing this notice in the Federal Register to announce final criteria for defining census tracts for the 2020 Census. Census tracts defined by these criteria will also be used to tabulate and publish estimates from the American Community Survey (ACS)
and potentially data from other Census Bureau censuses and surveys.
In addition to providing final criteria for census tracts, this notice contains a summary of comments received in response to proposed criteria published in the Federal Register on February 15, 2018 (83 FR 6941) as well as the Census Bureau's response to those comments. After publication of final criteria in the Federal Register, the Census Bureau will offer designated governments or organizations an opportunity to review and, if necessary, suggest updates to the boundaries and attributes of the census tracts in their geographic area through the Participant Statistical Areas Program (PSAP). The program also encompasses the review and update of census block groups, census designated places, and census county divisions.
I. History of Census Tracts
In 1905, Dr. Walter Laidlaw originated the concept of permanent, small geographic areas as a framework for studying change from one decennial census to another in neighborhoods within New York City. For the 1910 Census, eight cities—New York, Baltimore, Boston, Chicago, Cleveland, Philadelphia, Pittsburgh, and St. Louis—delineated census tracts (then termed “districts”) for the first time. No additional jurisdictions delineated census tracts until just prior to the 1930 Census, when an additional ten cities chose to do so. The increased interest in census tracts for the 1930 Census is attributed to the promotional efforts of Howard Whipple Green, who was a statistician in Cleveland, Ohio, and later the chairman of the American Statistical Association's Committee on Census Enumeration Areas. For more than twenty-five years, Mr. Green strongly encouraged local citizens, via committees, to establish census tracts Start Printed Page 56278and other census statistical geographic areas. The committees created by local citizens were known as Census Tract Committees, later called Census Statistical Areas Committees.
After 1930, the Census Bureau saw the need to standardize the delineation, review, and updating of census tracts and published the first set of census tract criteria in 1934. The goal of the criteria has remained unchanged; they assure comparability and data reliability through the standardization of the population thresholds for census tracts, as well as requiring that tracts' boundaries follow specific types of geographic features that do not change frequently. The Census Bureau began publishing census tract data as part of its standard tabulations beginning with the 1940 Census. Prior to that time, census tract data were published as special tabulations.
For the 1940 Census, the Census Bureau began publishing census block 
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.
For the 2010 Census, the Census Bureau adopted changes to census tract criteria that recognized their utility as a framework of small geographic areas for presenting and analyzing statistical and other data for a variety of communities, settlement patterns, and landscapes. The Census Bureau augmented its minimum, maximum, and optimum population threshold with housing unit thresholds for use in defining census tracts for seasonal communities that have no or low population on census day (April 1). The Census Bureau formalized criteria for census tracts defined for employment centers, airports, parks, large water bodies, and other special land uses that had been permitted in previous decades, but never specified within the criteria. The Census Bureau also established tribal census tracts as a geographic framework defined within federally recognized American Indian reservations and off-reservation trust lands that is fully separate from the standard census tracts defined within counties.
II. Summary of Comments Received in Response to the Proposed Criteria
The Federal Register published on February 15, 2018 (83 FR 6941) requested comment on the proposed census tract criteria for the 2020 Census. The proposed criteria were unchanged from the final criteria adopted for the 2010 Census.
The Census Bureau received comments from 16 individuals or groups of individuals on topics related to (1) use of non-visible political boundaries when defining census tracts; (2) use of employment data to define census tracts encompassing areas with substantial amounts of commercial, industrial, or other non-residential activity for the purpose of transportation planning; (3) maintaining historical comparability; and (4) accounting for statistical data reliability and quality when developing census tract criteria and defining individual census tracts. Commenters represented state and local government agencies, regional planning organizations and councils of governments, state data centers, non-governmental organizations, and academic researchers. Comments received by the Census Bureau are summarized below, as well as the Census Bureau's response to these comments.
1. Using Non-Visible Minor Civil Division Boundaries in Michigan as Census Tract Boundaries
The Census Bureau received three comments from individuals in Michigan noting that non-visible minor civil division (MCD) boundaries in Michigan should be permitted to be census tract boundaries for the 2020 Census as was the case in the past. The commenters correctly noted that in Table 1, Acceptable Minor Civil Division and Incorporated Place Boundaries, the proposed criteria were in error with regard to Michigan. The Census Bureau has corrected the table in the final criteria.
2. Defining Census Tracts on the Basis of Employment and Jobs
The Census Bureau received 14 comments related to defining census tracts encompassing areas with concentrations of employment and jobs or other types of non-residential uses to improve the utility of census tracts for transportation and journey-to-work analysis and planning. Eleven commenters suggested adoption of a minimum threshold of 1,200 workers/jobs (and no maximum or optimum thresholds) to be applied as an alternative to the existing minimum population or housing unit threshold or in combination with population or housing unit thresholds. One commenter supported the use of worker/job counts when defining census tracts, but did not specify a minimum threshold. Two commenters expressed support for modifying criteria for special use census tracts primarily to improve identification of census tracts encompassing areas with concentrations of employment. One commenter noted that applying employment thresholds was not necessary as the sample design for the American Community Survey (which is the source for much of the demographic data used in journey-to-work analysis) focused on residential population concentrations rather than employment concentrations. This commenter suggested that changes to the special use census tract land area criteria could achieve the result desired by commenters proposing employment thresholds and could provide greater flexibility when defining census tracts.
Based on consideration of the comments received on this topic and further discussion with stakeholders in the transportation community, the Census Bureau will change its criteria for defining special use census tracts to no longer specify minimum land area requirements. Special use census tracts should be comparable in land area size to surrounding census tracts to assure data reliability and quality when reporting on workplace-related data and to avoid data disclosure issues. The Census Bureau also recommends that, when defining special use census tracts encompassing employment centers and areas with concentrations of jobs, PSAP participants should strive for a minimum threshold of 1,200 workers/jobs.Start Printed Page 56279
3. Maintaining Historical Comparability
One commenter noted the importance of maintaining historical boundaries of census tracts for chronicling change in the sociodemographic characteristics of neighborhoods. The commenter noted that, while adherence to specified population thresholds (particularly the optimum and maximum population thresholds, which factor in decisions to split census tracts) is an important characteristic of census tracts, comparability over time also is a critical characteristic. Further, allowing census tracts to exceed the optimum and maximum thresholds will help mitigate issues related to the large sampling error associated with small geographic areas. The commenter suggested that by leaving census tract boundaries unchanged (i.e., by not splitting census tracts), local governments will be able to aggregate census tracts more easily to the neighborhood level, allowing for comparability over time as well as more reliable data. The commenter further suggested that if census tracts must be merged in order to meet the minimum population threshold, then an effort should be made to align the boundaries for block groups within the new census tract with the boundaries of the former census tracts.
The Census Bureau agrees with the sentiments expressed by this commenter and will continue to allow individual PSAP participants to avoid splitting census tracts if they are more concerned about historical comparability or statistical data reliability or both. We also agree with the suggestion to align block group boundaries with the boundaries of former census tracts in those instances in which census tracts have been merged and will update the final criteria accordingly.
4. Data Quality as an Explicit Criterion for Census Tracts
One comment, submitted by a team of researchers, centered around the quality and reliability of statistical data for census tracts and other small geographic areas. Their concern was that the current methodology for updating and defining census tracts, with its focus on maintaining historical comparability as well as adherence to the optimum threshold of 4,000 persons, results in a framework of small geographic areas that may not meet current analytical and policy development needs for statistically reliable data. Similar to the sentiment expressed by the comment discussed above, this group of commenters suggested that in some places and contexts, the population size of census tracts should be allowed to increase beyond the maximum threshold, adding that these larger units would provide higher quality data because they would contain more responses from sample-based surveys. However, in their suggestion regarding adoption of explicit statistical data quality criteria, the commenters are proposing a fundamental change in the process for defining census tracts for data dissemination purposes; that is, if a census tract does not achieve the quality criterion for a given data release, it would be combined with an adjacent tract. The commenters suggest that through this combination, the margins of error on the estimates will be reduced, and data users will be able to obtain a more reliable estimate for a new larger “census tract” (encompassing multiple “sub-tracts”).
While this is an intriguing idea, the Census Bureau cannot implement it at this time. Through the 2020 PSAP, the Census Bureau works with participants to update census tract boundaries prior to the 2020 Census to define a stable geographic framework for tabulating and presenting decennial census and ACS data. As we understand it, the commenters' proposal would result in a framework of “preliminary” census tracts that would be combined, as necessary, to meet statistical data reliability criteria after data have been tabulated, but prior to final release. The Census Bureau needs more time than is available prior to the start of the 2020 PSAP delineation process to research this proposal and consider any potential data tabulation, data disclosure, and analytical implications, particularly if census tracts were combined in different ways depending on the specific mix of variables presented in a particular data tabulation.
III. General Principles and Criteria for Census Tracts for the 2020 Census
A. General Principles
1. The primary goal of the census tract is to provide a set of nationally consistent small, statistical geographic units, with stable boundaries, that facilitate analysis of data across time. A century of census tract use, along with ACS and the averaging of sample data for tracts over a five-year span, has shown that continuity and comparability in tracts and their boundaries over time are of considerable importance to data users. Pursuant to this goal, the Census Bureau requests that where a census tract must be updated, for example to meet the minimum or maximum population or housing unit thresholds, that the outer boundaries of the tract not be changed, but rather that a tract be split into two or more tracts, or merged with an adjacent tract. The Census Bureau discourages changes to tract boundaries (that is, “retracting”), except in specified circumstances, which the Census Bureau will review on a case-by-case basis.
2. In order to ensure a minimal level of reliability in sample data and minimize potential disclosures of sensitive information, a census tract should contain at least 1,200 people or at least 480 housing units at minimum, and 8,000 people or 3,200 housing units at maximum. PSAP participants should aim to create census tracts that meet the optimal population of 4,000 or 1,600 housing units and maintain the minimum thresholds unless it is flagged as a special use tract (discussed below), or is coextensive with a county with fewer than 1,200 people. The housing unit criterion is used to accommodate areas that are occupied seasonally and may otherwise show a discrepancy between decennial and ACS figures.
3. The Census Bureau recognizes that there are significant geographic areas that are characterized by unique populations (e.g., prisons or universities) or not characterized by residential populations at all (e.g., National Parks, large bodies of water, or employment centers) which local participants may wish to exclude from populated census tracts for either analytical or cartographic purposes. These areas may be designated as special use census tracts to distinguish them from standard populated census tracts. Special land and/or water use census tracts are not required, but if delineated they must be designated as a specific type of special use (discussed below), have an official name, ideally have no residential population or housing units or at least meet all minimum population or housing thresholds mention above, and must not create noncontiguous census tracts. While there are no longer minimum land area measurement thresholds for special use tracts in urban or rural areas, such census tracts should be comparable in size to surrounding census tracts, particularly if defined to encompass employment centers or other areas containing a greater concentration of jobs than residents. The Census Bureau recognizes that some special use areas not intended for residential Start Printed Page 56280population, such as parks, may contain some minimal population, such as caretakers or those experiencing homelessness. Since the primary purpose of census tracts is to help provide high-quality statistical data about the population, the participant and the Census Bureau must decide if a special use tract would be useful in such a situation.
4. To facilitate the analysis of data for American Indian tribes, and to recognize their unique governmental status, program participants are encouraged to merge, split, or redefine census tracts to avoid unnecessarily splitting American Indian reservations (AIRs) and off-reservation trust lands (ORTLs). Each contiguous AIR and/or ORTL should be included, along with any necessary territory outside the AIR and/or ORTL, within a single census tract or as few census tracts as possible for the 2020 Census. This is the only situation in which retracting is encouraged (Figure 1).
The criteria herein apply to the United States, including federally recognized AIRs and ORTLs, 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 published criteria. In addition, the Census Bureau reserves the right to modify the boundaries and attributes of census tracts as needed to meet the published criteria and/or maintain geographic relationships before or after the final tabulation geography is set for the 2020 Census.
The Census Bureau sets forth the following criteria for use in reviewing, updating, and delineating 2020 Census tracts:
5. Census tracts must not cross county or state boundaries.
This criterion takes precedence over all other criteria or requirements (except for tribal tracts on federally recognized AIRs and/or ORTLs).
6. Census tracts must cover the entire land and water area of a county.
7. Census tracts must comprise a reasonably compact and contiguous land area.
Noncontiguous boundaries are permitted only where a contiguous area or inaccessible area would not meet population or housing unit count requirements for a separate census tract, in which case the noncontiguous or inaccessible area must be combined within an adjacent or proximate tract. For example, an island that does not meet the minimum population threshold for recognition as a separate census tract should be combined with other proximate land to form a single, contiguous census tract. Each case will be reviewed and accepted at the Census Bureau's discretion.
8. Census tract boundaries should follow visible and identifiable features.
To make the location of census tract boundaries less ambiguous, wherever possible, tract boundaries should follow significant, visible, easily identifiable features. The use of visible features facilitates the location and identification of census tract boundaries in the field, both on the ground and in imagery. The selection of permanent physical features also increases the stability of the boundaries over time, as the locations of many visible features in the landscape tend to change infrequently. If census tract boundaries are changed, they should not be moved from a more Start Printed Page 56281significant feature (e.g., a highway or a major river) to a less significant feature (e.g., a neighborhood road or a small tributary stream). By definition, state and county boundaries must be used as census tract boundaries. The Census Bureau also permits the use of incorporated place and minor civil division (MCD) boundaries in states where those boundaries tend to remain unchanged over time (see Table 1).
The following features are preferred as census tract boundaries for the 2020 Census:
a. State and county boundaries must always be census tract boundaries. This criterion takes precedence over all other boundary criteria or requirements.
b. AIR and ORTL boundaries.
c. Visible, perennial, stable, relatively permanent natural and constructed features, such as roads, shorelines, rivers, perennial streams and canals, railroad tracks, or above-ground high-tension power lines.
d. Boundaries of legal and administrative entities in selected states. Table 1 identifies by state which MCD and incorporated place boundaries may be used as census tract boundaries.
e. Additionally, the following legally defined, administrative boundaries would be permitted as census tract boundaries:
i. Barrio, barrio-pueblo, and sub-barrio boundaries in Puerto Rico;
ii. Census subdistrict and estate boundaries in the U.S. Virgin Islands;
iii. County and island boundaries (both MCD equivalents) in American Samoa;
iv. Election district boundaries in Guam;
v. Municipal district boundaries in the Commonwealth of the Northern Mariana Islands; and,
vi. Alaska Native Regional Corporation boundaries in Alaska, at the discretion of the Census Bureau, insofar as such boundaries are unambiguous for allocating living quarters as part of 2020 Census activities.
f. The boundaries of large parks, forests, airports, penitentiaries/prisons, and/or military installations, provided the boundaries are clearly marked or easily recognized in the field, in imagery, and on the ground.
g. When acceptable visible and governmental boundary features are not available for use as census tract boundaries, the Census Bureau may, at its discretion, approve other nonstandard visible features, such as major ridgelines, above-ground pipelines, intermittent streams, or fence lines. The Census Bureau may also accept, on a case-by-case basis, relatively short stretches of boundaries of selected nonstandard and potentially nonvisible features, such as cadastral and parcel boundaries or the straight-line extensions or other lines-of-sight between acceptable visible features.
Table 1—Acceptable Minor Civil Division (MCD) and Incorporated Place Boundaries
|State||All MCD boundaries||Boundaries of MCDs not co-incident with the boundaries of incorporated places that themselves are MCDs||All incorporated
boundaries||Only conjoint incorporated
|Start Printed Page 56282|
|a Townships only.|
|b Governmental townships only.|
9. Population, Housing Unit, and Area Measurement Thresholds
The following are the population, housing unit, and area measurement threshold criteria for census tracts (as summarized in Table 2). The same population and housing unit thresholds apply to all types of non-special use census tracts, including census tracts delineated for AIRs and ORTLs, the Island Areas, and encompassing group quarters, military installations, and institutions.
Table 2—Census Tract Thresholds
|Census tract type||Threshold type||Optimum||Minimum||Maximum|
|Standard & tribal census tracts||Population threshold Housing unit threshold||4,000 1,600||1,200 480||8,000. 3,200.|
|Special use census tracts||Area measurement||At least comparable in land area size to surrounding census tracts||At least comparable in land area size to surrounding census tracts||At least comparable in land area size to surrounding census tracts.|
| ||Employment threshold (suggested)||Suggested minimum of 1,200 workers or jobs.|
a. 2010 Census population counts should be used in census tract review in most cases. Housing unit counts should be used for census tracts in seasonal communities that have little or no population on Census Day (April 1). Locally produced population and housing unit estimates can be used when reviewing and updating census tracts, especially in areas that have experienced considerable growth since the 2010 Census.
b. The housing unit thresholds are based on a national average of 2.5 persons per household. The Census Bureau recognizes that there are local and regional variations to this average, and will take this into consideration when reviewing all census tract proposals.
c. Any census tract with a population or housing unit count less than the minimum threshold should be merged with an adjacent census tract to form a single tract with at least 1,200 people or at least 480 housing units (Figure 2). The Census Bureau recognizes the complexity that exists between meeting the optimum population or housing unit threshold in a census tract and maintaining census tract comparability over time. For example, if the population or housing unit count based on 2010 Census data was below the minimum thresholds, but significant growth has occurred since 2010 or is expected before 2020 for a census tract, the census tract should not be merged with another census tract. Supporting evidence may be requested by the Census Bureau. However, if the census tract's population does not increase as expected and does not meet either the minimum population or housing unit thresholds for 2020, this may adversely affect the reliability and availability of any sample estimates for that census tract. For this reason, the Census Bureau suggests merging the census tract with another adjacent census tract if there is a possibility that anticipated growth will not be sufficient to meet minimum thresholds. When merging census tracts, the Census Bureau suggests retaining the former census tract boundaries as boundaries for block groups within the newly defined census tract to facilitate historical analysis.
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d. For the 2020 Census, the Census Bureau will allow the delineation of special use census tracts, but they are not required. A special use census tract must be designated as a specific use type (e.g., state park), must have an official name (e.g., Jay Cooke State Park), have no (or very little) residential population or meet population or housing unit thresholds, and must not create a noncontiguous census tract. In some instances, multiple areas can be combined to form a single special use census tract if the land use or land management characteristics are similar, such as a special use census tract comprising an area with a concentration of employment or adjacent federal and state parks. Any resulting special use census tract should be at least as large in area as the surrounding standard, populated census tracts.
10. Identification of Census Tracts
a. A census tract has a basic census tract identifier composed of no more than four digits and may have a two-digit decimal suffix.
b. The range of acceptable basic census tract identifiers for the 2020 Census is from 1 to 9989 (see 6.c. below for exceptions); special use census tracts delineated specifically to complete coverage of large water bodies will be numbered from 9950 to 9989 in each county.
c. Census tracts delineated within or to primarily encompass AIRs and/or ORTLs should be numbered from 9400 to 9499.
d. Census tract identifiers must be unique within each county.
e. Once used, census tract identifiers cannot be reused in a subsequent census to reference a completely different area within a county. If a census tract is split, each portion may keep the same basic 4-digit identifier, but each portion must be given a unique suffix. If a census tract that was suffixed for 2010 Census is split, each portion must be given a new suffix.
f. The range of acceptable census tract suffixes is .01 to .98.
11. Census Tract Types
Table 3 provides a summary of the types of census tracts (with their respective population, housing unit, and area measurement thresholds) that the Census Bureau will use for the 2020 Census.
Table 3—Summary of Census Tract Types
|Census tract type||Distinction from standard census tract||Population thresholds||Housing unit thresholds||Area measurement thresholds|
|Standard census tract||Optimum: 4,000; Min: 1,200; Max: 8,000||Optimum: 1,600; Min: 480; Max: 3,200||None.|
|Tribal census tract||Tribal census tracts are conceptually similar and equivalent to census tracts defined within the standard state-county-tract geographic hierarchy used for tabulating and publishing statistical data||Optimum: 4,000; Min: 1,200; Max: 8,000||Optimum: 1,600; Min: 480; Max: 3,200||None.|
|Special use census tract||A census tract encompassing an employment center, large airport, public park, public forest, or large water body with no (or very little) population or housing units||None (or very little) or within the standard census tract threshold||None (or very little) or within the standard census tract threshold||At least comparable in size to surrounding standard census tracts.|
B. Tribal Census Tracts
Tribal census tracts are statistical geographic entities defined by the Census Bureau in cooperation with tribal officials to provide meaningful, relevant, and reliable data for small geographic areas within the boundaries of federally recognized AIRs and/or ORTLs. As such, they recognize the unique statistical data needs of federally recognized American Indian tribes. The delineation of tribal census tracts allows for an unambiguous presentation of census tract-level data specific to the federally recognized AIR and/or ORTL without the imposition of state or county boundaries, which might artificially separate American Indian populations located within a single AIR and/or ORTL. To this end, the American Start Printed Page 56284Indian tribal participant may define tribal census tracts that cross county or state boundaries, or both. For federally recognized American Indian tribes with AIRs and/or ORTLs that have more than 2,400 residents, the Census Bureau will offer the tribal government the opportunity to delineate tribal census tracts and other tribal statistical geography on their AIR and/or ORTL. For federally recognized tribes with an AIR and/or ORTL with fewer than 2,400 residents, the Census Bureau will define one tribal census tract coextensive with the AIR and/or ORTL. Tribal census tracts must be delineated to meet all other census tract criteria, and must be identified uniquely to clearly distinguish them from county-based census tracts. Tribal census tracts are conceptually similar and equivalent to census tracts defined within the standard state-county-tract geographic hierarchy used for tabulating and publishing statistical data.
In order to provide meaningful statistical geographic areas within the AIR and/or ORTL, as well as make meaningful and reliable data available for these areas and their populations, tribal census tract geography is maintained separately from standard county-based census tracts. This change was first introduced for the 2010 Census, creating standard, county-based census tracts nationwide and maintaining tribal census tracts as a completely separate set of geography from standard census tracts for both geographic and data presentation purposes. The change eliminated, in part, the reliability and availability data issues for the tribal census tracts and the derived standard census tracts that were present in Census 2000. 
As with standard census tracts submitted through this program, the tribal census tracts are submitted to the Census Bureau, and are subject to review to ensure compliance with the published criteria. Detailed criteria pertaining to tribal census tracts will be published in a separate Federal Register notice pertaining to all American Indian areas, including statistical areas defined through the PSAP.
IV. Definitions of Key Terms
Alaska Native Regional Corporation (ANRC)—A corporate geographic area established under the Alaska Native Claims Settlement Act (Pub. L. 92-203, 85 Stat. 688 (1971)) to conduct both the business and nonprofit affairs of Alaska Natives. Twelve ANRCs cover the entire state of Alaska except for the Annette Island Reserve.
American Indian off-reservation trust land (ORTL)—An area of land located outside the boundaries of an AIR, whose boundaries are established by deed, and which are held in trust by the U.S. federal government for a federally recognized American Indian tribe or members of that tribe.
American Indian reservation (AIR)—An area of land with boundaries established by final treaty, statute, executive order, and/or court order and over which a federally recognized American Indian tribal government has governmental authority. Along with “reservation,” designations such as colonies, communities, pueblos, rancherias, and reserves apply to AIRs.
Census block—Census blocks are statistical areas bounded by visible features, such as streets, roads, streams, and railroad tracks, and by non-visible boundaries, such as selected property lines and city, township, school district, and county limits and short line-of-sight extensions of streets and roads. Census blocks cover the entire territory of the United States, Puerto Rico, and the Island Areas.
Conjoint—A description of a boundary line shared by two adjacent geographic entities.
Contiguous—A description of areas sharing common boundary lines, more than a single point, such that the areas, when combined, form a single piece of territory. Noncontiguous areas form disjoint pieces.
Group quarters—A location where people live or stay, in a group living arrangement, that is owned or managed by an entity or organization providing housing and/or services for the residents. This is not a typical household-type living arrangement. These services may include custodial or medical care as well as other types of assistance, and residency is commonly restricted to those receiving these services. People living in group quarters are usually not related to each other. Group quarters include such places as college residence halls, residential treatment centers, skilled nursing facilities, group homes, military barracks, correctional facilities, and workers' dormitories.
Incorporated place—A type of governmental unit, incorporated under state law as a city, town (except in New England, New York, and Wisconsin), borough (except in Alaska and New York), or village, generally to provide governmental services for a concentration of people within legally prescribed boundaries.
Minor civil division (MCD)—The primary governmental or administrative division of a county in 28 states and the Island Areas having legal boundaries, names, and descriptions. The MCDs represent many different types of legal entities with a wide variety of characteristics, powers, and functions depending on the state and type of MCD. In some states, some or all of the incorporated places also constitute MCDs.
Nonvisible feature—A map feature that is not visible on the ground such as a city or county boundary through space, a property line, or line-of-sight extension of a road.
Retracting—Substantially changing the boundaries of a census tract so that comparability over time is not maintained.
Special use census tract—Type of census tract that must be designated as a specific use type (e.g., state park or large lake) and have an official name (e.g., Jay Cooke State Park or Lake Minnetonka), should have no (or very little) population or housing units, and must not create a noncontiguous census tract. If delineated in a densely populated, urban area, a special use census tract must have an area of at least one square mile. If delineated completely outside an urban area, a special use census tract must have an area of at least 10 square miles.
Visible feature—A map feature that can be seen on the ground and in imagery, such as a road, railroad track, major above-ground transmission line or pipeline, river, stream, shoreline, fence, sharply defined mountain ridge, or cliff. A nonstandard visible feature is a feature that may not be clearly defined on the ground (such as a ridge), may be seasonal (such as an intermittent stream), or may be relatively impermanent (such as a fence). The Census Bureau generally requests verification that nonstandard features used as boundaries for the PSAP geographic areas pose no problem in their location during field work.
End Supplemental Information
Dated: October 30, 2018.
Ron S. Jarmin,
Deputy Director, Performing the Non-Exclusive Functions and Duties of the Director, Bureau of the Census.
[FR Doc. 2018-24567 Filed 11-9-18; 8:45 am]
BILLING CODE 3510-07-P