US Urbanized Areas
Notes & Caveats


An urbanized area is a densely populated area (built up area) with a population density of more than 1,000 per square mile with a population of more than 50,000. This definition is independent of corporate city or regional government boundaries.

An urbanized area is considerably different from a metropolitan area. Metropolitan areas typically include large tracts of non-urbanized (non- developed land). This is because, outside the six New England states, metropolitan areas are defined by county borders. As a result, for example, the Los Angeles metropolitan area (Consolidated Metropolitan Statistical Area) covers more than 34,000 square miles, only 2,000 of which are in the Los Angeles urbanized area. Thus, metropolitan Los Angeles metropolitan covers nearly the same area as the state of Indiana, while the urbanized area is equal to only six of Indiana's seven counties in square miles.

The following more descriptive definition is provided by the US Census Bureau:

The Census Bureau delineates urbanized areas (UA's) to provide a better separation of urban and rural territory, population, and housing in the vicinity of large places. A UA comprises one or more places ("central place") and the adjacent densely settled surrounding territory ("urban fringe") that together have a minimum of 50,000 persons. The urban fringe generally consists of contiguous territory having a density of least 1,000 persons per square mile. The urban fringe also includes outlying territory of such density if it was connected to the core of the contiguous area by road and is within 1 1/2 road miles of that core, or within 5 road miles of the core but separated by water or other undevelopable territory. Other territory with a population density of fewer than 1,000 people per square mile is included in the urban fringe if it eliminates an enclave or closes an indentation in the boundary of the urbanized area. The population density is determined by (1) outside of a place, one or more contiguous census blocks with a population density of at least 1,000 persons per square mile or (2) inclusion of a place containing census blocks that have at least 50 percent of the population of the place and a density of at least 1,000 persons per square mile. The complete criteria are available from the Chief, Geography Division, U.S. Bureau of the Census, Washington, DC 20233.

Urbanized area data was first collected in the 1950 census.

Data provided for all 34 urbanized areas in the United States with a population of 1,000,000 or more in any decennial census from 1950 to 1990 (33 urbanized areas had populations exceeding 1,000,000 in 1990. Buffalo exceeded 1,000,000 in 1980 and before). Some metropolitan areas with populations above 1,000,000 have not yet achieved that population in their urbanized areas. Examples include Indianapolis, Columbus and Charlotte.

Central city data is for the cities indicated in the urbanized area name. The US Census Bureau has added a number of additional smaller cities as central cities, but these have been excluded for data consistency.

Fort Lauderdale was not designated as an urbanized area until the 1960 census.

(c) 2000 --- Wendell Cox Consultancy --- Permission granted to use with attribution.
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