They are variously designated as American Indian reservations, assessment districts, boroughs, election districts, gores, grants, magisterial districts, parish governing authority districts, plantations, precincts, purchases, supervisors' districts, towns, and townships. The Census Bureau recognizes MCDs in 28 States. The boundaries of CCDs usually are delineated to follow visible features, and in most cases coincide with census tract or block numbering area boundaries. Places are for the reporting of decennial census data, include census-designated places, consolidated cities, and incorporated places. CDPs comprise densely settled concentrations of population that are identifiable by name, but are not legally incorporated places.
City includes both consolidated city and incorporated places, discussed in places .
ZIP Codes usually do not have clearly identifiable boundaries, 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. An MA comprises one or more central counties. An MA also may include one or more outlying counties that have close economic and social relationships with the central county. Each state has at least one district. In four States there are one or more cities that are independent of any county organization and thus constitute primary divisions of their States.