Metropolitan Area

Metropolitan areas are large population centers (central cities) together with their adjacent zones of influence, where influence may be measured by levels of commuting to the central city or by commercial ties and media penetration—thus typically encompassing rural areas and physically separate satellite towns that are economically integrated with the core city.

Metropolitan areas were an innovation of the U.S. Census, first called “metropolitan districts” in 1930 and only fully developed as “metropolitan areas” for the 1950 Census. Areas were recognized around independent central cities of 50,000 or more people and, for most of the country, consisted of the county containing the central city plus adjacent counties with “significant” ties to the central county, in particular commuting levels of 15% or more to the central city ...