A census-designated place (CDP)
CDPs have been used in each decennial census since 1980 as the counterparts of incorporated places, such as self-governing cities, towns, and villages, for the purposes of gathering and correlating statistical data. CDPs are populated areas that generally include one officially designated but currently unincorporated community, for which the CDP is named, and may include surrounding inhabited countryside of varying dimensions and, occasionally, other, smaller unincorporated communities. CDPs include small rural communities, edge cities, colonias located along the Mexico–United States border, and unincorporated resorts and retirement communities and their environs. The boundaries of any CDP may change from decade to decade, and the Census Bureau may de-establish a CDP after a period of study, then re-establish it some decades later. Most unincorporated areas within the United States are not and have not been included in any CDP.
The boundaries of a CDP have no legal status and may not always correspond with the local understanding of the area or community with the same name. However, criteria established for the 2010 census require that a CDP name "be one that is recognized and used in daily communication by the residents of the community" (not "a name developed solely for planning or other purposes") and recommend that a CDP's boundaries be mapped based on the geographic extent associated with inhabitants' regular use of the named place. There is no provision, however, that this name recognition be unanimous for all residents, or that all residents use the community for which the CDP is named for services provided therein. There is no mandatory correlation between CDP names or boundaries and those established for other human purposes, such as post office names or zones, political precincts, or school districts. In addition, census city lists from 2007 included Arlington County, Virginia's CDP in the list with the incorporated places, but since 2010, only the Urban Honolulu CDP, Hawaii, representing the historic core of Honolulu, Hawaii, is shown in the city and town estimates.
History
The Census Bureau reported data for some unincorporated places as early as the first census in 1790 (for example, Louisville, Kentucky, which was not legally incorporated in Kentucky until 1828), though usage continued to develop through the 1890 census, in which the census mixed unincorporated places with incorporated places in its products with "town" or "village" as its label.
The 1900 through 1930 censuses did not report data for unincorporated places. The PSAP was to be offered to county and municipal planning agencies in 2008.
Effects of designation and examples
The boundaries of such places are typically defined in cooperation with local county or tribal officials, but are not fixed, and do not affect the status of local government or incorporation; the territories thus defined are strictly statistical entities. CDP boundaries may change from one census to the next to reflect changes in settlement patterns.