2018-02625. Census Tracts for the 2020 Census-Proposed Criteria

AGENCY:

Bureau of the Census, Commerce

ACTION:

Notice of proposed program and request for comments

SUMMARY:

The Census Bureau is publishing this notice in the Federal Register to request comments from the public and other government agencies on census tracts. 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 of the census tracts in their geographic area under the Participant Statistical Areas Program (PSAP). In addition to reviewing and updating census tracts, the program also reviews and updates census block groups, census designated places, census county divisions, and statistical tribal geographic areas. The Census Bureau will issue notices in the Federal Register for each of these geographies.

DATES:

Written comments must be submitted on or before May 16, 2018.

ADDRESSES:

Please direct all written comments on this proposed program to Vincent Osier, Geographic Standards, Criteria, and Quality Branch, Geography Division, U.S. Census Bureau, Room 4H173, 4600 Silver Hill Road, Washington, DC 20233-7400. Email: [e-mail]. Phone: [phone], or 301-763-3056 (PSAP Hotline).

FOR FURTHER INFORMATION CONTACT:

Requests for additional information on this proposed program should be directed to Vincent Osier, Geographic Standards, Criteria, and Quality Branch, Geography Division, U.S. Census Bureau, Room 4H173, 4600 Silver Hill Road, Washington, DC 20233-7400. Email: [e-mail]. Phone: [phone], or 301-763-3056 (PSAP hotline).

SUPPLEMENTARY INFORMATION:

Census tracts are relatively permanent small-area geographic divisions of a county or statistically equivalent entity ^[1] defined for the tabulation and presentation of data from the decennial census and selected other statistical programs. Census tracts will also be used to tabulate and publish estimates from the American Community Survey (ACS) ^[2] after 2020 and potentially data from other Bureau of the Census (Census Bureau) censuses and surveys.

There are no proposed changes to the existing census tract criteria from the 2010 Census; this notice provides only clarifications. The history of census tracts and changes implemented for the 2010 Census can be found in the Federal Register from March 14, 2008 (73 FR 13836).

I. 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 has shown that continuity and comparability in tracts and their boundaries over time are of considerable importance to data users. Pursuant to this goal of maintaining continuity and comparability in tracts, the Census Bureau requests that the outer boundaries of the tract not be changed when a census tract must be updated, for example to meet the minimum or maximum population or housing unit thresholds. Instead, Census requests that updates to a tract split the tract into two or more tracts, or merge the tract 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 1,200 people or 480 housing units at minimum, and 8,000 people or 3,200 housing units at maximum. A census tract should maintain these 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. PSAP participants should aim to create census tracts that meet the optimal population of 4,000 or 1,600 housing units. The housing unit criterion is used to accommodate areas that are occupied seasonally and may otherwise show a discrepancy between decennial and ACS population figures.^[3]

3. The Census Bureau also recognizes that there are significant geographic areas that are characterized by unique populations (e.g., prisons or universities) or not characterized by residential populations at all (e.g., national parks or large bodies of water) which local participants may wish to exclude from populated 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 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 mentioned above, and must not create noncontiguous census tracts. If located in an urban area, a special use census tract must have an area measurement of approximately one square mile or more. If delineated completely outside an urban area, a special use census tract must have an area of approximately 10 square miles or more. The Census Bureau recognizes that some special use areas not intended for residential population, such as parks, may contain some minimal population, such as caretakers or the homeless; 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 census 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).

B. Criteria

The criteria herein apply to the United States, including federally recognized AIRs and ORTLs, Puerto Rico, and the Island Areas.^[4] 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:

1. 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).

2. Census tracts must cover the entire land and water area of a county.

3. 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.

4. Census tract boundaries should follow visible and identifiable features.

To make the location of census tract boundaries less ambiguous, wherever possible, tract boundaries should follow 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 significant feature (e.g., a highway or a major river) to a less significant feature (e.g., a neighborhood road or a small tributary stream). 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 subbarrio boundaries in Puerto Rico;

ii. Census subdistrict and estate boundaries in the U.S. Virgin Islands;

iii. County and island boundaries (both MCD equivalents) in American Samoa;

iv. Election district boundaries in Guam;

v. Municipal district boundaries in the Commonwealth of the Northern Mariana Islands; and

vi. Alaska Native Regional Corporation boundaries in Alaska, at the discretion of the Census Bureau, insofar as such boundaries are unambiguous for allocating living quarters as part of 2020 Census activities.

f. The boundaries of large parks, forests, airports, penitentiaries/prisons, and/or military installations, provided the boundaries are clearly marked or easily recognized in the field in imagery and on the ground.

g. When acceptable visible and governmental boundary features are not available for use as 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 place boundaries	Only conjoint incorporated place boundaries
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		X
Indiana	X			X
Iowa		X b		X
Kansas		X a		X
Kentucky				X
Louisiana				X
Maine	X		X
Maryland				X
Massachusetts	X		X	X
Michigan				X
Minnesota				X
Mississippi				X
Missouri				X
Montana				X
Nebraska				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
Tennessee		X		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.

5. Population, Housing Unit, and Area Measurement Thresholds.

The following are the population, housing unit, and area measurement threshold criteria for census tracts (as summarized in Table 2). 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 threshold within an urban area	none	1 square mile	none.
Area measurement threshold outside an urban area	none	10 square miles	none.
	Population threshold	None (or very little), or must be within the standard census tract thresholds.

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.

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), must 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 management characteristics are similar, such as a special use census tract comprising adjacent federal and state parks. If the special use census tract is delineated in a densely populated, urban area, the census tract must have an area of approximately one square mile or more. If the special use census tract is delineated completely outside an urban area, the census tract must have an area of approximately 10 square miles or more. Any resulting special use census tract should be at least as large in area the adjacent standard, populated census tracts.

6. Identification of Census Tracts.

a. The Census Bureau assigned each census tract 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; special use census tracts delineated specifically to complete coverage of large water bodies will be numbered from 9950 to 9989 in each county; census tracts delineated within or to primarily encompass AIRs and/or ORTLs should be numbered from 9400 to 9499.

c. Census tract identifiers must be unique within each county.

d. 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.

e. The range of acceptable census tract suffixes is .01 to .98.

7. Census Tract Types.

Table 3 provides a summary of the types of census tracts (with their respective population, housing unit, and area measurement thresholds) that the Census Bureau will use for the 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 a 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	Within an urban area: min. 1 square mile; Outside an urban area: min. 10 square miles.

C. 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 Indian 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 that has 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 so as 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, and eliminating, 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.^[5]

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.

II. 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.

Block group—A statistical subdivision of a census tract consisting of all census blocks whose numbers begin with the same digit in a census tract. A block group is the smallest geographic entity for which the Census Bureau normally tabulates sample data.

Census block—A geographic area bounded by visible and/or invisible features shown on a map prepared by the Census Bureau. A block is the smallest geographic entity for which the Census Bureau tabulates and publishes decennial census data.

Census county division (CCD)—Areas delineated by the Census Bureau in cooperation with state, tribal, and local officials for statistical purposes. CCDs have no legal function and are not governmental units. CCD boundaries usually follow visible features and usually coincide with census tract boundaries. The name of each CCD is based on a place, county, or well-known local name that identifies its location.

Census designated place (CDP)—A statistical geographic entity equivalent to an incorporated place with a concentration of population, housing, and commercial and nonresidential structures that is identifiable by name, but is not within an incorporated place.

Census tract—A small, relatively permanent statistical geographic division of a county defined for the tabulation and publication of Census Bureau data. The primary goal of census tracts is to provide a set of nationally consistent, relatively small, statistical geographic units, with stable boundaries that facilitate analysis of data across time and between decennial censuses.

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), must have little or no 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.

Dated: January 31, 2018.

Ron S. Jarmin,

Associate Director for Economic Programs, Performing the Non-Exclusive Functions and Duties of the Director, Bureau of the Census.

Footnotes

1.  For the Census Bureau's purposes, the term “county” includes parishes in Louisiana; boroughs, city and boroughs, municipalities, and census areas in Alaska; independent cities in Maryland, Missouri, Nevada, and Virginia; districts and islands in American Samoa; districts in the U.S. Virgin Islands; municipalities in the Commonwealth of the Northern Mariana Islands; municipios in Puerto Rico; and the areas constituting the District of Columbia and Guam. This notice will refer to all these entities collectively as “counties”.

2.  The ACS is conducted in the United States and in Puerto Rico. In Puerto Rico the survey is called the Puerto Rico Community Survey. 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.

3.  `Occupied seasonally' refers to seasonal communities in which residents often are not present on the date of the decennial census, but will be present at other times of the year and for which estimates may be reflected in the ACS. The ACS is designed to produce local area data based upon a 12-month period estimate (or an average).

4.  For Census Bureau purposes, the United States typically refers to only the fifty states and the District of Columbia, and does not include the U.S. territories (Puerto Rico, the Island Areas, and the U.S. Minor Outlying Islands). The Island Areas includes American Samoa, the Commonwealth of the Northern Mariana Islands, Guam, and the U.S. Virgin Islands. The U.S. Minor Outlying Islands are an aggregation of nine U.S. territories: Baker Island, Howland Island, Jarvis Island, Johnston Atoll, Kingman Reef, Midway Islands, Navassa Island, Palmyra Atoll, and Wake Island.

5.  For Census 2000, tribal tracts were defined for federally recognized AIRs and/or ORTLs 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 AIR and/or ORTL. In such instances, the state-county portions of a tribal tract were identified as individual census tracts. These standard census tracts may not have met the minimum population thresholds, potentially limiting sample data reliability or availability for both the tribal tract and the derived standard census tracts.