The County of San Diego was established by the State Legislature on February 18, 1850, as one of the original 27 counties of California.

The San Diego County Board of Supervisors held its first meeting on January 3, 1853 when the County was divided into supervisorial districts.

Included in the original county boundary were the present counties of San Diego, Imperial, Riverside, San Bernardino, and the eastern portion of Inyo County. Today, San Diego County covers approximately 4,255 square miles - 65 miles from north to south and 86 miles from east to west.

The County draws its name from San Diego de Alcala, a designation credited to Spaniard Don Sebastian Vizcaino who sailed into what is now San Diego Bay on November 12, 1603. The site was actually discovered 61 years earlier by Juan Rodriguez Cabrillo who had named it San Miguel.

San Diego County is the third most populous of California's 58 counties, with estimated 2,883,600 residents in 2001. It ranks 6th in population of all metropolitan areas in the U.S. and is one of the most ethnically diverse metropolitan areas in the nation.

Bi-national trade and tourism is estimated at over $15 billion annually. The San Diego County Gross Regional Product for 2001 was estimated to be $120.5 billion, and ranked thirty-fifth worldwide among national economies. San Diego County median household income is $51,000 for 2002.