San Joaquin County, officially the County of San Joaquin, is a county located in the U.S. state of California. As of the 2020 census, the population was 779,233. The county seat is Stockton. San Joaquin County comprises the Stockton–Lodi–Tracy metropolitan statistical area within the regional San Jose–San Francisco–Oakland combined statistical area…San Joaquin County, officially the County of San Joaquin, is a county located in the U.S. state of California. As of the 2020 census, the population was 779,233. The county seat is Stockton. San Joaquin County comprises the Stockton–Lodi–Tracy metropolitan statistical area within the regional San Jose–San Francisco–Oakland combined statistical area. The county is located in Northern California's Central Valley just east of the very highly populated nine-county San Francisco Bay Area region and is separated from the Bay Area by the Diablo Range, having access to the Bay Area via the Altamont Pass. One of the smaller counties by area in California, it has a high population density and is growing rapidly due to overflow from the Bay Area.