Contra Costa County

As one of the original 27 counties created by the California Legislature in 1850, Contra Costa County is nestled in the northern portion of the San Francisco Bay Area’s East Bay region. The City of Martinez is the county seat. The county’s name, which means “opposite coast,” refers to its position on the other side of the bay, and reflects its Spanish heritage dating back to the Mexican land grant days of the 1830s. That influence can still be found today in community names such as Acalanes, Los Medanos, Las Juntas, Pacheco, and Mt. Diablo, which dominates the county landscape at 3,849 feet above sea level.

Many notable figures came from the area including conservationist John Muir and legendary baseball great Joe DiMaggio. California's first doctor, John Marsh, settled in 1837 on a large land grant that is now called Marsh Creek.