San Joaquin County, California

San Joaquin County
Nickname: 
"Sanwa"
Motto: 
"Greatness grows here."
Interactive map of San Joaquin County
Location in the state of California
CountryUnited States
StateCalifornia
RegionSan Joaquin Valley
IncorporatedFebruary 18, 1850
Named afterSan Joaquin River, which was named for St. Joachim
County seatStockton
Largest cityStockton
Government
 • TypeCouncil–Administrator
 • BodyBoard of Supervisors
 • ChairSonny Dhaliwal
 • Vice ChairSteven J. Ding
 • Board of Supervisors
Supervisors
  • Mario Gardea
  • Paul Canepa
  • Sonny Dhaliwal
  • Steven J. Ding
  • Robert Rickman
 • County AdministratorJerome C. Wilverding
Area
 • Total
1,426 sq mi (3,690 km2)
 • Land1,391 sq mi (3,600 km2)
 • Water35 sq mi (91 km2)
Highest elevation
3,629 ft (1,106 m)
Population
 (2020)
 • Total
779,233
 • Estimate 
(2024)
816,108
 • Density560.2/sq mi (216.3/km2)
GDP
 • Total$40.227 billion (2022)
Time zoneUTC−8 (Pacific Standard Time)
 • Summer (DST)UTC−7 (Pacific Daylight Time)
Area codes209, 350
FIPS code06-077
GNIS feature ID277303
Congressional districts9th, 13th
Websitewww.sjgov.org

San Joaquin County (/ˌsæn hwɑːˈkn/ SAN whah-KEEN; Spanish: San Joaquín, meaning "St. Joachim"), officially the County of San Joaquin, is located in the U.S. state of California. As of the 2020 United States census, the population was 779,233. The county seat is Stockton.

San Joaquin County comprises the StocktonLodiTracy metropolitan statistical area within the regional San JoseSan FranciscoOakland 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. It is separated from the East Bay partly by the Diablo Range, through which there is road and rail access to Alameda County via the Altamont Pass, and partly by the Sacramento-San Joaquin Delta, through which there are links to Contra Costa County via road, rail, and shipping, and to Solano County via road. 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.

The City of San Joaquin, despite sharing its name with the county, is located in Fresno County.