Census Geography:

Areas for Which Data is Available from the U.S. Census

 

Census block
A subdivision of a census tract (or, prior to 2000, a block numbering area), a block is the smallest geographic unit for which the Census Bureau tabulates 100-percent data. Many blocks correspond to individual city blocks bounded by streets, but blocks -- especially in rural areas - may include many square miles and may have some boundaries that are not streets. The Census Bureau established blocks covering the entire nation for the first time in 1990. Previous censuses back to 1940 had blocks established only for part of the nation. Over 8 million blocks are identified for Census 2000.

Census tract
A small, relatively permanent statistical subdivision of a county delineated by a local committee of census data users for the purpose of presenting data. Census tract boundaries normally follow visible features, but may follow governmental unit boundaries and other non-visible features in some instances; they always nest within counties. Designed to be relatively homogeneous units with respect to population characteristics, economic status, and living conditions at the time of establishment, census tracts average about 4,000 inhabitants. They may be split by any sub-county geographic entity.

Place
A concentration of population either legally bounded as an incorporated place, or identified as a Census Designated Place (CDP) including comunidades and zonas urbanas in Puerto Rico. Incorporated places have legal descriptions of borough (except in Alaska and New York), city, town (except in New England, New York, and Wisconsin), or village

Central city
The largest city of a Metropolitan area (MA). Central cities are a basis for establishment of an MA. Additional cities that meet specific criteria also are identified as central cities. In a number of instances, only part of a city qualifies as central, because another part of the city extends beyond the MA boundary.

Metropolitan statistical area (MSA)
A geographic entity defined by the federal Office of Management and Budget for use by federal statistical agencies, based on the concept of a core area with a large population nucleus, plus adjacent communities having a high degree of economic and social integration with that core. Qualification of an MSA requires the presence of a city with 50,000 or more inhabitants, or the presence of an Urbanized Area (UA) and a total population of at least 100,000 (75,000 in New England). The county or counties containing the largest city and surrounding densely settled territory are central counties of the MSA. Additional outlying counties qualify to be included in the MSA by meeting certain other criteria of metropolitan character, such as a specified minimum population density or percentage of the population that is urban. MSAs in New England are defined in terms of minor civil divisions, following rules concerning commuting and population density

Consolidated metropolitan statistical area (CMSA)
A geographic entity defined by the federal Office of Management and Budget for use by federal statistical agencies. An area becomes a CMSA if it meets the requirements to qualify as a metropolitan statistical area, has a population of 1,000,000 or more, if component parts are recognized as primary metropolitan statistical areas, and local opinion favors the designation.

Primary metropolitan statistical area (PMSA)
A geographic entity defined by the federal Office of Management and Budget for use by federal statistical agencies. If an area meets the requirements to qualify as a metropolitan statistical area and has a population of one million or more, two or more PMSAs may be defined within it if statistical criteria are met and local opinion is in favor. A PMSA consists of one or more counties (county subdivisions in New England) that have substantial commuting interchange. When two or more PMSAs have been recognized, the larger area of which they are components then is designated a consolidated metropolitan statistical area.

Metropolitan area (MA)
A collective term, established by the federal Office of Management and Budget, to refer to metropolitan statistical areas, consolidated metropolitan statistical areas, and primary metropolitan statistical areas.

Economic place
A statistical subdivision of a state delineated according to Census Bureau guidelines for the purpose of presenting economic census data. Economic places include incorporated places of 2,500 or more people, county subdivisions of 10,000 or more people in 12 designated states, and census designated places in Hawaii. Any residual area within a state is delineated into Economic places so as not to cross the boundaries of any consolidated city, county subdivision in 12 designated states, metropolitan area in New England, or county.