San Joaquin County is located in Central Valley of the U.S. state of California, just east of the San Francisco Bay Area. As of 2006, the population is approx. 620,000. The county seat is Stockton. San Joaquin County was one of the original counties of California, created in 1850 and takes its name from the San Joaquin River. The county has a total area of 1,426 miČ, 98% of it is land and 2% of it is water. San Joaquin County is also home to the site of the San Joaquin Valley's first permanent residence. As of 2000, the population density was 403/miČ.