Alameda (Spanish for "a place where poplar trees grow") is one of the 58 counties in the state of California. It was one of three counties formed in 1853 in California, and was created from parts of Contra Costa and Santa Clara counties. As of the 2010 census, the population was 1,510,271, up from 1,442,741 in 2000. The county seat and largest city is Oakland.
Alameda County has an area of 821.15 square miles (2,126.8 km2), of which 737.57 sq mi (1,910.3 km2) is land. It is bordered on the north by Contra Costa County, the east by San Joaquin County, Stanislaus County on the southeast, and Santa Clara County on the south. There are also bridge links to San Francisco and San Mateo counties to the west.
Alameda is one of the traditional nine Bay Area counties.