Contra Costa County

County in north-central California, USA; area 1,891 sq km/730 sq mi; population (1990) 803,700. The county is situated along the San Francisco, San Pablo, and Suisun bays and the Carquinez Strait (to the north). Its seat is Martinez. The county has important ports, including Richmond, and industrial cities, including Pittsburg, Concord, Antioch, and Hercules. Steelworks, refineries, shipyards, and food processing plants are here. In the eastern part of the county, Contra Costa produces asparagus, fruit, nuts, wine, grapes, grains, sugar beets, dairy goods, and livestock. Stone, clay, sand, and gravel are also important. Suburban residential growth characterizes much of the southwestern part of the county.