Contra Costa County, California Contra Costa County County seat Martinez Largest city Concord (population and land area) Richmond (total area) Government • Type Council–CAO33 more rows
Nortonville, California. Nortonville is an unincorporated ghost town in Contra Costa County, California. It was located on Kirker Creek 5.5 miles (9 km) north-northeast of Mount Diablo, at an elevation of 801 feet (244 m).
County seat, Martinez. Created February 18, 1850. The name signifies “opposite coast,” because of its situation opposite San Francisco, in an easterly direction, on San Francisco Bay.
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.
The county has a strong economy, with major industries including healthcare, education, and technology. Some of the largest employers in Contra Costa County include Kaiser Permanente, Chevron, and the Mount Diablo Unified School District.