Contra Costa County is located in the San Francisco Bay Area of California. It is the ninth most populous county in the state. The county seat is Martinez.

The county is governed by a five-member Board of Supervisors, which is elected by the residents of the county. The Board of Supervisors is responsible for setting policy and overseeing the county's departments and services.

The county is divided into five supervisorial districts, each of which is represented by one of the five supervisors. The county also has a number of departments and services, including public safety, health services, parks and recreation, libraries, and public works.

The county is home to several cities, including Concord, Walnut Creek, Richmond, and Pittsburg. It also includes several unincorporated communities, such as Bay Point, El Sobrante, and Crockett.

The county is served by two major airports, Oakland International Airport and San Francisco International Airport. It is also served by several major highways, including Interstate 80, Interstate 680, and Highway 4.

The county is home to several higher education institutions, including Diablo Valley College, Contra Costa College, and California State University East Bay.

For the most up-to-date and in-depth information, please check the public records links below.