As defined for the 1980 census, urban areas  (a) places of 2,500 or more inhabitants incorporated as cities, villages, boroughs (except Alaska and New York) and towns (except in the New England states, New York and Wisconsin), but excludes those persons living in the rural portions of extended cities; (b) census designated places of 2,500 or more inhabitants; and (c) other areas, incorporated or unincorporated, included in urbanized areas.
Urban areas have more than 2 million residents.