A corporate entity established to conduct both business and nonprofit affairs of Alaska Natives, pursuant to the Alaska Native Claims Settlement Act of 1972 (Public Law 92-203, as amended). Twelve ANRCs are legally bounded geographic entities that cover Alaska, except for the Annette Islands Reserve (an American Indian reservation). A thirteenth ANRC represents Alaska Natives who do not live in Alaska and do not identify with any of the 12 corporations; the U.S. Census Bureau does not present data for this ANRC.

A local governmental unit in Alaska that constitutes an association, band, clan, community, group, tribe, or village, recognized pursuant to the Alaska Native Claims Settlement Act of 1972 (Public Law 92-203, as amended). ANVs do not have clearly defined boundaries that are easily locatable, and they often include many square miles of land used by Alaska Natives for hunting and fishing, so the U.S. Census Bureau works with officials of the Alaska Native villages and Alaska Native Regional Corporations to delineate Alaska Native village statistical areas for data presentation purposes.

A statistical entity that represents the settled portion of an Alaska Native village for data presentation purposes.

The United States holds title for specific area in trust for the benefit of an American Indian tribe (tribal trust land) or for an individual American Indian (individual trust land). Although trust land may be located on or off a reservation, the U.S. Census Bureau recognizes and tabulates data only for off-reservation trust land. Census data always associate off-reservation trust land with a specific federally recognized reservation and/or tribal government. See American Indian reservation, American Indian trust land.

A federal American Indian reservation is an area that has been set aside by the United States for the use of one or more federally recognized American Indian tribes. Together with off-reservation trust land, a reservation covers territory over which one or more tribes have primary governmental authority. The boundary of a federal reservation is defined by tribal treaty, agreement, executive or secretarial order, federal statute, or judicial determination. A state American Indian reservation is an area that a state government has allocated to a tribe recognized by that state, but not by the federal government. American Indian reservations are known as colonies, communities, Indian communities, Indian villages, pueblos, rancherias, ranches, reservations, reserves, and villages. See American Indian off-reservation trust land, American Indian tribal subdivision, American Indian trust land, joint use area.

A legal subdivision of a federally recognized American Indian reservation, off-reservation trust land, or Oklahoma tribal statistical area. These entities are internal units of self-government or administration that serve social, cultural, and/or economic purposes for American Indians living on a reservation, off-reservation trust land, or Oklahoma tribal statistical area. Tribal subdivisions are known as areas, chapters, communities, districts, and segments. The U.S. Census Bureau previously provided unpublished data for these entities for the 1980 census, which referred to them as American Indian subreservation areas.

An area for which the United States holds title in trust for the benefit of an American Indian tribe (tribal trust land) or for an individual American Indian (individual trust land). Trust land may be located on or off a reservation; however, the U.S. Census Bureau recognizes and tabulates data only for off-reservation trust land. See American Indian off-reservation trust land, Hawaiian home land.

The U.S. Census Bureau recognizes barrios and barrios-pueblo as the primary legal divisions of municipios. These entities are similar to the minor civil divisions (MCDs) used for reporting decennial census data in 28 states of the United States. Subbarrios in 23 municipios are the primary legal subdivisions of the barrios-pueblo and some barrios. The Census Bureau presents the same types of Census 2000 data for these "sub-MCDs" as it does for the barrios and barrios-pueblo. Each barrio, barrio-pueblo, and subbarrio is assigned a five-digit Federal Information Processing Standards (FIPS) code in alphabetical order within Puerto Rico. See subbarrio.

See census block

The features that delimit a census block. The features may be visible (a street, road, stream, shoreline, power line, etc.) or invisible (a county line, city limit, property line, imaginary extension of a street or road, etc.). Generally, the boundary of a census block must include at least one addressable feature; that is, a street or road. For data tabulation, the boundary of every legal and statistical entity recognized in the U.S. Census Bureau's standard data tabulations is a block boundary.

A statistical subdivision of a census tract (or, prior to Census 2000, a block numbering area). A BG consists of all tabulation blocks whose numbers begin with the same digit in a census tract. For example, for Census 2000, BG 3 within a census tract includes all blocks numbered from 3000 to 3999. (A few BGs consist of a single block.) BGs generally contain between 300 and 3,000 people, with an optimum size of 1,500 people. The BG is the lowest-level geographic entity for which the U.S. Census Bureau tabulates sample data from a decennial census. See tribal block group.

A number assigned to each census block.

* For collecting information for Census 2000, each census block was identified uniquely within a county (or statistically equivalent entity) by a 4- or 5-digit number, which could be followed by an alphabetic suffix. All the collection blocks within a county used the same number of digits.

* For tabulating data for Census 2000, each census block is identified uniquely within a census tract by a 4-digit number. A 1990 census block number had three digits, and might include an alphabetic suffix.

Prior to Census 2000, a statistical subdivision of a county or statistically equivalent entity, delineated by a state government agency or a U.S. Census Bureau regional census center for the purpose of grouping and numbering census blocks in counties that did not have census tracts. BNAs were discontinued for Census 2000; they were replaced by census tracts in every county and statistically equivalent entity.

A legally established geographic entity in Alaska, which the Census Bureau treats as statistically equivalent to a county in other states; a minor civil division in each of the five counties that comprise New York city; a type of incorporated place in Connecticut, New Jersey, and Pennsylvania.

A statistical entity that serves as the equivalent of a county in Alaska. Census areas are delineated cooperatively by the state of Alaska and the U.S. Census Bureau for the purpose of presenting census data for the portion of Alaska not within an organized borough, city and borough, or municipality.

A geographic area bounded by visible and/or invisible features shown on a map prepared by the U.S. Census Bureau. A block is the smallest geographic entity for which the Census Bureau tabulates decennial census data. See block boundary, block number.

Any map, in electronic or paper form, produced by the U.S. Census Bureau. Such a map usually displays the boundaries and names and/or codes of the geographic entities that the Census Bureau uses to take a census or survey, or for which the Census Bureau tabulates data, and may include both visible and invisible features, feature names, and other information appropriate to the purpose for which the map was prepared. Some Census Bureau maps display statistical data in various thematic forms. Every Census Bureau map displays a credit note showing that it was produced by the U.S. Census Bureau.

A statistical subdivision of a county, established and delineated cooperatively by the U.S. Census Bureau and state, local, and tribal officials for data presentation purposes. CCDs have been established in 21 states that do not have minor civil divisions suitable for data presentation; that is, minor civil divisions have not been legally established, do not have governmental or administrative purposes, have boundaries that are ambiguous or change frequently, and/or generally are not well known to the public.

A geographic entity that serves as the statistical counterpart of an incorporated place for the purpose of presenting census data for an area with a concentration of population, housing, and commercial structures that is identifiable by name, but is not within an incorporated place. CDPs usually are delineated cooperatively with state, Puerto Rico, Island Area, local, and tribal officials based on U.S. Census Bureau guidelines. For Census 2000, for the first time, CDPs did not need to meet a minimum population threshold to qualify for the tabulation of census data. See place. Note: A CDP in Puerto Rico is called a comunidad or zona urbana.

A grouping of states and the District of Columbia, established by the U.S. Census Bureau for the presentation of census data. The nine divisions represent areas that were relatively homogeneous when they were established in 1910. The divisions are subdivisions of the four census regions.

A collective term referring to the geographic entities used by the U.S. Census Bureau in its data collection and tabulation operations, including their relationships to one another. See geographic hierarchy, tabulation geography.

See Census Bureau map.

A grouping of states and the District of Columbia, established by the U.S. Census Bureau for the presentation of census data. The four regions represent areas that were relatively homogeneous when they were established in 1910 and revised in 1950. Each region is divided into two or three census divisions.

A statistical subdivision of a borough, census area, or other entity that is the statistical equivalent of a county in Alaska. A census subarea is similar to a census county division in other states. Census subareas are delineated cooperatively by the state of Alaska and the U.S. Census Bureau.

A small, relatively permanent statistical subdivision of a county or statistically equivalent entity, delineated for data presentation purposes by a local group of census data users or the geographic staff of a regional census center in accordance with U.S. Census Bureau guidelines. Designed to be relatively homogeneous units with respect to population characteristics, economic status, and living conditions at the time they are established, census tracts generally contain between 1,000 and 8,000 people, with an optimum size of 4,000 people. Census tract boundaries are delineated with the intention of being stable over many decades, so they generally follow relatively permanent visible features. However, they may follow governmental unit boundaries and other invisible features in some instances; the boundary of a state or county (or statistically equivalent entity) is always a census tract boundary. When data are provided for American Indian entities, the boundary of a federally recognized American Indian reservation and off-reservation trust land is always the boundary of a tribal census tract. See block numbering area, tribal census tract.

A 4-digit number, which may be followed by a 2-digit decimal suffix, used to identify a census tract uniquely within a county or statistically equivalent entity. For Census 2000, census tract numbers range from 0001 to 9999, with 9400 to 9499 reserved for census tracts related to federally recognized American Indian reservations and off-reservation trust land - primarily reservations and trust land that cross county lines. Leading zeros and a suffix of ".00" usually do not appear on maps prepared by the U.S. Census Bureau, and are not commonly used when referring to a particular census tract. The number "0000" in computer-readable files identifies a census tract delineated to provide complete coverage of water area in territorial seas and the Great Lakes.

In a metropolitan area, the largest place and, in some areas, one or more additional places that meet official standards. A few primary metropolitan statistical areas do not have a central city.

In an urbanized area or urban cluster, the largest incorporated place, or census designated place in some cases, and one or more additional places that meet specific criteria. For an urbanized area or urban cluster that does not contain an incorporated or census designated place, there is no central place (the title of the urbanized area or urban cluster uses the name of a minor civil division, or a local place name recognized by the Board on Geographic Names and recorded by the U.S. Geological Survey, but the name does not represent a central place).

A type of incorporated place in all states and the District of Columbia. In agreement with the state of Hawaii, the U.S. Census Bureau does not recognize the city of Honolulu for presentation of census data. In Virginia, all cities are not part of any county, and so the Census Bureau treats them as equivalent to a county for data presentation purposes, as well as treating them as places; there also is one such independent city in each of three states: Maryland, Missouri, and Nevada. In 23 states and the District of Columbia, some or all cities are not part of any minor civil division, in which case the Census Bureau treats them as county subdivisions as well as places for data presentation purposes.

A legally established geographic entity in Alaska, which the U.S. Census Bureau treats as the statistical equivalent of a county in other states; also, a type of incorporated place in Alaska. This designation is new for Census 2000.

See geographic code.

The smallest area that the U.S. Census Bureau used to collect information for the decennial census. A collection block may be split by the boundary of any legal or statistical entity later recognized by the Census Bureau for census data presentation. Thus, if a collection block is split by one or more legal and/or statistical boundaries, each portion will be a separate tabulation block; if a collection block is not split, the same area may be a tabulation block. See block number, census block, tabulation block.

A census designated place in Puerto Rico that is not related to a municipio's seat of government. See census designated place, zona urbana.

One of the 435 areas from which people are elected to the U.S. House of Representatives. The CDs for which Census 2000 first provides data are those for the 106th Congress.

The U.S. Census Bureau refers to a governmental unit for which the functions of an incorporated place and its county or minor civil division have merged as a consolidated government. If one or more other incorporated places continue to function as separate governmental units even though they are part of a consolidated government, the Census Bureau refers to the primary incorporated place as a consolidated city.

A geographic entity designated by the federal Office of Management and Budget (OMB) for use by federal statistical agencies. An area becomes a consolidated metropolitan statistical area (CMSA) if it qualifies as a metropolitan area (MA), has a census population of 1,000,000 or more, has component parts that qualify as primary metropolitan statistical areas (PMSAs) based on official standards, and local opinion favors the designation. CMSAs consist of whole counties except in New England, where they consist of county subdivisions (primarily cities and towns). See central city, metropolitan area, metropolitan statistical area, New England County Metropolitan Area, primary metropolitan statistical area, statistical entity.

The primary legal division of every state except Alaska and Louisiana. A number of geographic entities are not legally designated as a county, but are recognized by the U.S. Census Bureau as equivalent to a county for data presentation purposes. These include the boroughs, city and boroughs, municipality, and census areas in Alaska; parishes in Louisiana; and cities that are independent of any county in Maryland, Missouri, Nevada, and Virginia. They also include the municipios in Puerto Rico, districts and islands in American Samoa, municipalities in the Northern Mariana Islands, and islands in the Virgin Islands of the United States. Because they contain no primary legal divisions, the Census Bureau treats the District of Columbia and Guam each as equivalent to a county (as well as equivalent to a state) for data presentation purposes. In American Samoa, a county is a minor civil division.

The primary legal or statistical division of a county or statistically equivalent entity. See census county division, census subarea, minor civil division, unorganized territory.

See census division.

See extended place.

A place that contains both urban and rural territory; i.e., an incorporated place or census designated place that is partially within and partially outside of an urbanized area or urban cluster. The term is first used for Census 2000. Previously referred to as an extended city, which applied only to incorporated places, subject to very specific criteria.

A code, consisting of one or more alphanumeric or special-text characters, used to identify a geographic entity. Every geographic entity recognized by the Census Bureau is assigned one or more geographic codes. Also referred to as a geocode.

A spatial unit of any type, legal or statistical, such as the United States, a state, county, county subdivision, place, census tract, block group, or census block. See census geography, legal entity, statistical entity.

A geographic presentation that shows the geographic entities in a superior/subordinate structure. In this system of relationships among geographic entities, each entity (except the smallest one) is subdivided into lower-order units that in turn may be subdivided further. For example, states are subdivided into counties, which are subdivided into both county subdivisions and census tracts. The Census Bureau uses three sets of hierarchies: one is based on states and counties; another on American Indian area, Alaska Native areas, and Hawaiian home lands; and a third on metropolitan or urban areas. See census geography, tabulation geography.

A geographic entity established by legal action for the purpose of implementing specified general- or special-purpose governmental functions. Most GUs have legally established boundaries and names, and have officials (usually elected) who have the power to carry out legally prescribed functions, provide services for the residents of the GU, and raise revenues. Some GUs do not have officials or do not implement the powers that the law entitles them to; the U.S. Census Bureau refers to these entities as inactive governmental units.

An area held in trust for the benefit of native Hawaiians by the state of Hawaii, pursuant to the Hawaiian Homes Commission Act of 1920, as amended. Hawaiian home lands are a new type of geographic entity for Census 2000.

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 a wide array of specific governmental services for a concentration of people within legally prescribed boundaries. New for Census 2000 are "city and borough" and "municipality," which serve as both place- and county-level entities in Alaska. A few incorporated places do not have a legal description. See consolidated city, governmental unit, independent city, independent place, place.

An incorporated place that is independent of - i.e., not part of - any county. All incorporated places classified as cities in Virginia are independent cities, as are Baltimore, MD; St. Louis, MO; and Carson City, NV. The U.S. Census Bureau treats an independent city as equivalent to a county and, where appropriate, as a county subdivision and as an incorporated place for data presentation purposes.

In a state in which the Census Bureau recognizes minor civil divisions (MCDs), an incorporated place that is not legally part of any MCD. The Census Bureau treats an independent place as equivalent to a county subdivision and as an incorporated place for data presentation purposes. Independent places exist in 23 states and the District of Columbia.

See American Indian reservation.

For Census 2000, several legal entities under the jurisdiction of the United States: American Samoa, Guam, the Commonwealth of the Northern Mariana Islands, and the Virgin Islands of the United States. The U.S. Census Bureau treats these entities as equivalent to states for data presentation purposes. The term also includes several small islands in the Caribbean Sea and Pacific Ocean; the Census Bureau provides only population counts for these "U.S. Minor Outlying Islands," based on records obtained from the government agency that administers each island (most are unpopulated). Formerly referred to as the Outlying Areas.

Territory that is administered, claimed, and/or used by two or more American Indian tribes. It may consist of an overlap of territory of adjoining American Indian reservations or Oklahoma tribal statistical areas, or off-reservation trust land for one tribe that is located within the reservation of another tribe. Such territory was referred to as joint area for the 1990 census.

A geographic entity whose origin, boundary, name, and description result from charters, laws, treaties, or other administrative or governmental action, including the United States; the 50 states, the District of Columbia, Puerto Rico, and the Island Areas; counties and statistically equivalent legal entities; minor civil divisions; incorporated places, including consolidated cities; American Indian reservations, off-reservation trust land, and tribal subdivisions; Alaska Native Regional Corporations; Hawaiian home lands; congressional districts; state legislative districts; most voting districts; and school districts. Some legal entities, such as Hawaiian home lands, congressional districts, and voting districts, have no governmental officials or powers, but serve only as nonfunctioning administrative entities. The legal entities and their boundaries that the U.S. Census Bureau recognizes for Census 2000 are those that existed on January 1, 2000. See governmental unit, statistical entity.

A core areas with a large population nucleus, together with adjacent communities that have a high degree of economic and social integration with that core. (Some MAs are defined around two or more nuclei.) MAs are designated by the federal Office of Management and Budget (OMB) in terms of one or more counties or, in New England, county subdivisions (primarily cities and towns). The OMB defines and designates metropolitan areas based on a set of official standards that are published in the Federal Register. "Metropolitan area" is a collective term established by the OMB in 1990 to refer to metropolitan statistical areas (MSAs), consolidated metropolitan statistical areas (CMSAs), primary metropolitan statistical areas (PMSAs), and New England County Metropolitan Areas (NECMAs).

Note: In 2003, a new set of standards will go into effect, creating several new types of statistical entities and renaming others, and discontinuing the term "metropolitan area."

A geographic entity designated by the federal Office of Management and Budget for use by federal statistical agencies. A metropolitan statistical area (MSA) is a metropolitan area (MA) that is not closely associated with another MA. An MSA consists of one or more counties, except in New England, where MSAs are defined in terms of county subdivisions (primarily cities and towns). See central city, consolidated metropolitan statistical area, metropolitan area, New England County Metropolitan Area, primary metropolitan statistical area, statistical entity.

A type of governmental unit that is the primary governmental or administrative division of a county or statistically equivalent entity in many states and statistically equivalent entities. MCDs are identified by a variety of terms, such as township, town (in eight states), or district. The U.S. Census Bureau recognizes MCDs in 28 states, the District of Columbia, Puerto Rico, and the Island Areas. In 20 states and American Samoa, all or many MCDs are active general-purpose governmental units. Many MCDs are not general-purpose governmental units, and therefore do not have elected officials to carry out legal functions; instead, they serve as nonfunctioning administrative entities. See county subdivision, governmental unit, independent place, legal entity.

A legally established entity in Alaska and the Northern Mariana Islands. The U.S. Census Bureau treats this entity as the statistical equivalent of a county, and the Census Bureau also treats the municipality (Anchorage) in Alaska as an incorporated place. This designation in Alaska is new for Census 2000.

A governmental unit that is the primary legal division of Puerto Rico. The U.S. Census Bureau treats a municipio as equivalent to a county in the United States for data presentation purposes.

A county-based area designated by the federal Office of Management and Budget to provide an alternative to the county subdivision-based metropolitan statistical areas and consolidated metropolitan statistical areas in New England. See central city, metropolitan area, statistical entity.

See American Indian off-reservation trust land.

A statistical entity identified and delineated by the U.S. Census Bureau in consultation with federally recognized American Indian tribes in Oklahoma that once had a reservation in that state. An OTSA encompasses an area that conforms to a tribe's reservation that was dissolved preceding the establishment of Oklahoma as a state in 1907. For some OTSAs, neighboring tribes agreed to modify the boundary for data presentation purposes. Referred to as a tribal jurisdiction statistical area (TJSA) for the 1990 census and by a single all-encompassing entity called the "Historic Areas of Oklahoma (excluding urbanized areas)" for the 1980 census.

See Island Areas.

A governmental unit that is the primary legal subdivision of Louisiana. The U.S. Census Bureau treats a parish as equivalent to a county in other states for data presentation purposes.

A concentration of population either legally bounded as an incorporated place, or delineated for statistical purposes as a census designated place (in Puerto Rico, a comunidad or zona urbana). See census designated place, consolidated city, incorporated place, independent city, independent place.

A geographic entity designated by the federal Office of Management and Budget for use by federal statistical agencies. If an area that qualifies as a metropolitan area (MA) has a census population of one million or more, two or more primary metropolitan statistical areas (PMSAs) may be defined within it if they meet official standards and local opinion favors the designation. When PMSAs are established within an MA, that MA is designated a consolidated metropolitan statistical area (CMSA). See central city, consolidated metropolitan statistical area, metropolitan area, statistical entity.

An area for which the U.S. Census Bureau reports voting district (VTD) data, even though the boundary of the actual voting district was adjusted by the reviewing officials, for purposes of data presentation, so that it no longer matches the legally established boundary. See voting district.

A geographic entity for which the U.S. Census Bureau provides specially selected extracts of raw information from a small sample of long-form census records that are screened to protect confidentiality of census records. The extract files are referred to as public use microdata samples (PUMS). Public use microdata areas (PUMAs), which must have a minimum census population of 100,000 and cannot cross a state line, receive a 5-percent sample of the long-form records; these records are presented in state files. These PUMAs are aggregated into super-PUMAs, which must have a minimum census population of 400,000 and receive a 1-percent sample in a national file. The Census Bureau provided a 10-percent sample file each for Guam and the Virgin Islands of the United States. Data users can use these files to create their own statistical tabulations and data summaries.

See census region.

All territory, population, and housing units located outside of urbanized areas and urban clusters. See urban.

A geographic entity within which state, county, or local officials or the U.S. Department of Defense provides public educational services for an area's residents. The U.S. Census Bureau provides data for three types of school districts: elementary, secondary, and unified.

A primary governmental division of the United States. The U.S. Census Bureau treats the District of Columbia as the equivalent of a state for data presentation purposes. It also treats a number of entities that are not legal divisions of the United States as the equivalent of states for data presentation purposes: Puerto Rico and the Island Areas.

A statistical entity delineated for an American Indian tribe that does not have a land base (reservation) and is recognized as a tribe by a state government, but not the federal government. State designated American Indian statistical areas (SDAISAs) are identified and delineated for the U.S. Census Bureau by a state liaison identified by the governor's office. A SDAISA generally encompasses a compact and contiguous area that contains a concentration of people who identify with a state recognized American Indian tribe and in which there is structured or organized tribal activity. A SDAISA may not be located in more than one state unless the tribe is recognized by both states, and it may not include area within an American Indian reservation, off-reservation trust land, Oklahoma tribal statistical area, tribal designated statistical area, or Alaska Native village statistical area. SDAISAs were included with tribal designated statistical areas for the 1990 census; this designation is new for Census 2000.

The area represented by a member of the upper or lower chamber of a state legislature (or, for Nebraska, the unicameral legislature).

A geographic entity that is specially defined and delineated so that the U.S. Census Bureau may tabulate data for it. Statistical entities include census areas (in Alaska), census county divisions, census subareas (in Alaska), unorganized territories, census designated places, Oklahoma tribal statistical areas, tribal designated statistical areas, state designated American Indian statistical areas, Alaska Native village statistical areas, metropolitan areas, urban areas, census tracts, block groups, and census blocks. Designation as a statistical entity neither conveys nor confers legal ownership, entitlement, or jurisdictional authority. See legal entity.

A legal subdivision of a barrio or barrio-pueblo (minor civil division) in 23 municipios in Puerto Rico. (There is no geographic entity in the United States equivalent to a subbarrio.) Census 2000 provides the same types of data for subbarrios as it does for barrios and barrios-pueblo. Each subbarrio is assigned a five-digit Federal Information Processing Standards (FIPS) code in alphabetical order within Puerto Rico. See barrio, barrio-pueblo; sub-MCD.

A legal subdivision of a minor civil division (MCD). For Census 2000, only Puerto Rico has sub-MCDs (subbarrios).

See public use microdata area.

The smallest area for which the U.S. Census Bureau provides decennial census data. A tabulation block cannot be split by the boundary of any legal or statistical entity recognized by the Census Bureau for census data presentation. See block number, census block.

The geographic entities for which the U.S. Census Bureau tabulates and presents data. See geographic entity, geographic hierarchy.

See census tract.

A statistical entity delineated by state and/or local transportation officials for tabulating traffic-related data - especially journey-to-work and place-of-work statistics - from a decennial census. A TAZ usually consists of one or more census blocks, block groups, or census tracts.

A block group within a tribal census tract. Where a census tract numbered in the 9400 series crosses a county line, a tribal block group may be located on both sides of that boundary. See block group, tribal census tract.

A census tract within a federally recognized American Indian reservation and/or off-reservation trust land. Some of these census tracts are numbered in the 9400 series, primarily if they cross a county line. See census tract, tribal block group.

A statistical entity delineated for the U.S. Census Bureau by a federally recognized American Indian tribe that does not have a land base (a federally recognized reservation or off-reservation trust land). A TDSA generally encompasses a compact and contiguous area that contains a concentration of people who identify with a federally recognized American Indian tribe and in which there is structured or organized tribal activity. A TDSA may not include area within an American Indian reservation, off-reservation trust land, Oklahoma tribal statistical area, state designated American Indian statistical area, or Alaska Native village statistical area. For the 1990 census, it could not cross a state line, but it may do so for Census 2000. For the 1990 census, TDSAs included state-recognized tribes without a land base; these are now called state designated American Indian statistical areas.

See Oklahoma tribal statistical area.

See American Indian tribal subdivision.

See American Indian trust land.

The 50 states and the District of Columbia.

In a state in which the U.S. Census Bureau provides data for minor civil divisions (MCDs), the portion of a county that is not included in a legally established MCD or in an incorporated place that is independent of an MCD. For data presentation purposes, the Census Bureau recognizes such area as one or more separate county subdivisions, each designated as an unorganized territory. For Census 2000, ten states contain one or more UTs.

All territory, population, and housing units located within urbanized areas and urban clusters. See rural, urban area.

A generic term that refers to both urbanized areas and urban clusters. This terminology is new for Census 2000.

A densely settled area that has a census population of 2,500 to 49,999. A UC generally consists of a geographic core of block groups or blocks that have a population density of at least 1,000 people per square mile, and adjacent block groups and blocks with at least 500 people per square mile. A UC consists of all or part of one or more incorporated places and/or census designated places; such a place(s) together with adjacent territory; or territory outside of any place. See central place, extended place, urban, urbanized area.

Note: Any urban area delineated in Guam is classified as an urban cluster regardless of its population size.

In Oregon, an "urban growth boundary" is delineated around each incorporated place or a group of incorporated places by state and local officials, and subsequently confirmed in state law, to control urban development. The U.S. Census Bureau refers to the resulting geographic entities as "urban growth areas" (UGAs). UGAs are new for Census 2000. ("Urban growth boundary" is a legal term; "urban growth area" is a census term.)

A densely settled area that has a census population of at least 50,000. A UA generally consists of a geographic core of block groups or blocks that have a population density of at least 1,000 people per square mile, and adjacent block groups and blocks with at least 500 people per square mile. A UA consists of all or part of one or more incorporated places and/or census designated places, and may include additional territory outside of any place. See central place, extended place, urban, urban cluster.

The generic name for a geographic entity - such as an election district, precinct, or ward - established by state, local, and tribal governments for the purpose of conducting elections. Some reviewing officials adjusted the boundaries of the voting districts (VTDs) they submitted to conform to census block boundaries for data presentation purposes, and therefore a VTD for which Census 2000 provides data might not exactly represent the legal entity; the U.S. Census Bureau refers to such VTDs as pseudo-voting districts (pseudo-VTDs). Such VTDs, as well as any territory for which state officials did not specify a status, are identified by a "P" in the VTD indicator field of the PL data file.

The addresses served by a 5-digit ZIP Codea - established by the U.S. Postal Service to expedite the delivery of mail. Most ZIP Codes do not have specific boundaries, and their implied boundaries do not necessarily follow clearly identifiable visible or invisible map features; also, the carrier routes for one ZIP Code may intertwine with those of one or more other ZIP Codes, and therefore this area is more conceptual than geographic. See ZIP Code tabulation area.

A statistical entity developed by the U.S. Census Bureau to approximate the delivery area for a U.S. Postal Service 5-digit or 3-digit ZIP Codea in the United States and Puerto Rico. A ZCTA is an aggregation of census blocks that have the same predominant ZIP Code associated with the mailing addresses in the Census Bureau's Master Address File. Thus, the Postal Service's delivery areas have been adjusted to encompass whole census blocks so that the Census Bureau can tabulate census data for the ZCTAs. For areas larger than 25 square miles for which the Census Bureau's Master Address File contained no addresses with ZIP Codes, the Census Bureau used the first 3 digits of the ZIP Code(s) that serve the area or nearby areas. For the dress rehearsal data, there are two blank spaces after such 3-digit codes; for Census 2000, there is a suffix of "XX." A water feature that could not logically be assigned to a specific ZCTA is assigned a 3-digit code followed by "HH" to indicate that the water feature could not be assigned meaningfully to any adjacent land ZCTA. ZCTAs do not include all ZIP Codes used for mail delivery. The Census Bureau first created ZCTAs for the Census 2000 dress rehearsal census. See ZIP Code area.

In Puerto Rico, a census designated place consisting of the municipio seat of government and the adjacent built-up area. A zona urbana cannot extend across its municipio's boundary. See census designated place, comunidad.