As it has done with every decennial census since 1950, in late February 2013, the Office of Management and Budget announced the latest delineation of metropolitan areas in the United States. ERS uses this delineation as the foundation for its Rural-Urban Continuum Codes and Urban Influence Codes, which further identify each county by size of metro core (for metro counties), or degree of urbanization and proximity to metro areas (for nonmetro counties). Generally, nonmetro counties that grew rapidly over the previous decade are reclassified as metro. In the latest update, 113 nonmetro counties (with just under 5.9 million people) switched to metro status while 36 counties (with just over 1 million people) no longer qualified as metro, resulting in a net nonmetro population "loss" of 4.8 million from reclassification. The 1,976 counties now classified as nonmetro include 15 percent of the U.S. population (46 million people) and 72 percent of the Nation’s land area. This map is found on the ERS topic page, Population & Migration, updated May 2013.
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