The Region : L.A. County: Largest Population Hike

Los Angeles County, which is the nation’s most populous, had the largest numerical growth since 1980, adding 818,700 people to reach 8.3 million people, the Census Bureau announced Sunday. Maricopa County, Ariz., which includes Phoenix, came in second with 391,000 new residents, followed by Harris County, Tex., up 388,800; San Diego County, 339,500, and Dallas County, Tex.; 276,700. Rust Belt counties experienced the largest losses in population between April 1, 1980, when the last major census was taken, and July 1, 1986, according to the bureau. Wayne County, Mich., where Detroit is located, led the nation with a decline of 173,500; followed by Allegheny County, Pa., the home of Pittsburgh, down 76,600, and Cuyahoga County, Ohio, where Cleveland is located, down 53,000.