Geography Terms
- Block Groups
- Subdivisions of Census Tracts, each generally contain between 600 and 3,000 people, with an optimum size of 1,500 people.
- CBSA (Core Based Statistical Area)
- The Office of Management and Budget (OMB) reviewed the Metropolitan Area standards in 1999 and 2000. The new standards replace the current metropolitan area classification with a Core-Based Statistical Area (CBSA) classification. The new Core-Based Statistical Area (CBSA) consists of a county containing an Incorporated Place or Census Designated Place with a population of at least 10,000 along any adjacent counties that have at least 25% of employed residents of the county who work in the CBSAs core or central county. CBSAs are categorized as being either Metropolitan (core population of at least 50,000) or Micropolitan (core population between 10,000 and 50,000). This allows common statistics to be collected for less urban areas of the nation. These two county-based CBSA definitions will cover approximately 90% of the U.S. population.
- CCD (Census county division)
- CCDs are county subdivisions that were delineated by the U.S. Census Bureau, in cooperation with state and local officials for purposes of presenting statistical data. CCDs have been established in 21 states where there are no legally established minor civil divisions (MCDs), where the MCDs do not have governmental or administrative purposes, where the boundaries of the MCDs change frequently, and/or where the MCDs generally are not known to the public. CCDs have no legal functions and are not governmental units.
- CDP (Census Designated Place)
- See Place
- Census Block
- The smallest geographical area, bounded by visible boundaries, for which census data are collected. Census blocks make up census block groups that make up census tracts.
- Census Block Group
- Subdivisions of census tracts, each generally contain between 600 and 3,000 people, with an optimum size of 1,500 people.
- Census Tract
- A small, permanent subdivision of a county with homogeneous population characteristics, status and living conditions.
- City
- Type of incorporated place in 49 states and the District of Columbia. In 23 states and the District of Columbia, some or all cities are not part of any Minor Civil Division (MCD), and the Census Bureau also treats these as county subdivisions, statistically equivalent to MCDs.
- CMSA (Consolidated Metropolitan Statistical Area)
- Geographic entity defined by the federal Office of Management and Budget (OMB) for use by federal statistical agencies in the U.S. An area becomes a CMSA if it meets the requirements to qualify as a metropolitan statistical area (MSA), has a population of 1,000,000 or more, if component parts are recognized as primary metropolitan statistical areas (PMSAs), and local opinion favors the designation. Whole counties are components of CMSAs outside of New England, where they are composed of cities and towns instead.
- County
- The primary political administrative subdivision of a state, the county is widely used for marketing purposes for the following reasons: 1) The range and reliability of currently available data below the state level is greatest at the county level. 2) County geographic boundaries are rarely altered. 3) Complete national coverage is achieved by summarizing all counties. 4) County boundaries are readily identifiable.
- For Louisiana, parishes are used in lieu of counties; for Alaska, boroughs and census areas. The District of Columbia is treated as a single county unit. In Virginia, all cities are by law independent of counties; therefore they are treated as county units. The cities of Baltimore, MD, St. Louis, MO and Carson City, NV are also independent and therefore classified as counties.
- Custom Radius
- A specific street address or intersection with data aggregated for 1 or multiple radii from it or bands around it.
- DMA (Designated Market Area)
- The formal term for what is more commonly known as a TV or broadcast market. Definitions for DMAs are supplied by Nielsen Media Research that generates ratings for broadcast programming. DMAs are selected by totaling the viewer hours of TV stations whose signals reach a particular county with total hours, then converted to a percentage share of all viewing hours. DMAs are named for the market of origin of the station(s) with the largest share of viewer hours, and all counties whose largest viewer share is given to stations in that same market of origin are grouped together under that DMA.
- NOTE: Because of the reach of broadcast signals, DMAs don't always conform to whole-county geography like metro markets or newspaper markets. In certain cases, Nielsen splits counties, treating each portion as if it were a separate county. Each county, or portion thereof, is allocated to a single DMA, eliminating any geographic overlap. DMAs cover the whole U.S., except for parts of Alaska.
- MCD (Minor Civil Division)
- MCDs are the primary governmental or administrative divisions of a county or county equivalent in many states. MCDs represent many different kinds of legal entities with a wide variety of governmental and/or administrative functions. MCDs are variously designated as American Indian reservations, assessment districts, boroughs, charter townships, election districts, election precincts, gores, grants, locations, magisterial districts, parish governing authority districts, plantations, precincts, purchases, road districts, supervisor's districts, towns, and townships.
- MSA (Metropolitan Statistical Area)
- A geographic area with a significant population nucleus, along with any adjacent communities that have a high degree of economic and social integration with that nucleus.
- NECMA (New England County Metropolitan Area)
- The U.S. Office of Information and Regulatory Affairs (OIRA), a division of the government's Office of Management and Budget, designates these alternative areas, composed of whole counties, in the six New England states for use with data not available below the county level. A NECMA includes, in addition to the county containing the principal central city of an MSA, any other county with at least half its population in that MSA.
- Place
- A concentration of population either legally bounded as an incorporated place, or identified as a Census Designated Place (CDP). 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.
- State
- The primary legal subdivision of the United States. The District of Columbia (Washington, DC) is treated as the statistical equivalent of a state for census purposes.
- United States
- The 50 states and the District of Columbia.
- ZIP Code
- Administrative units established by the United States Postal Service (USPS) for the efficient distribution of mail. ZIP codes generally do not respect political or census statistical area boundaries, nor do they usually have clearly identifiable boundaries. In addition, ZIP codes often serve a continually changing area, are changed periodically to meet postal requirements and do not cover all the land area of the United States. The first three digits of the five-digit code identify a major city or sectional distribution center while the last two digits signify a specific post office delivery area or point.