Contra Costa County
County in California
Contra Costa County is a county located in the U.S. state of California, in the East Bay of the San Francisco Bay Area. As of the 2020 United States Census, the population was 1,165,927. The county seat is Martinez. Wikipedia
Cities: Martinez, Concord, Walnut Creek, and more
Population: 1.157 million (2022)
Superintendent: Lynn Mackey
Area code: 510, 341, 925
Congressional districts: 8th, 9th, 10th
County seat: Martinez
Highest elevation: 3,852 ft (1,174 m)