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Contra Costa County


Facts & Information

The Cities and communities of Contra Costa County, California *

Alamo, Antioch

Bay Point, Bethel Island, Blackhawk, Brentwood, Byron

Clayton, Concord, Crockett

Danville, Discovery Bay

El Cerrito, El Sobrante


Kensington, Knightsen


Martinez, Moraga

Oakley, Orinda

Pacheco, Pinole, Pittsburg, Pleasant Hill

Richmond, Rodeo

San Pablo, San Ramon

Walnut Creek

*This list of cities may not be complete. The list may contain towns, cities, villages, boroughs, neighborhoods, townships, ghost towns and other populated places.

If you have information about any of these unlinked communities, please send it to us and we will add a page for that community. Some of these places above may only be neighborhoods or local area names and are not listed with the census at all or just included in a larger surrounding designated census area..

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Information & Facts about Contra Costa County, California


Contra Costa County website

County Administration Building
651 Pine Street
Martinez, CA 94553
Phone: 925-646-4080
Fax: 925-646-4098

Martinez is the County Seat of Contra Costa County

As of April 2002, the County has 19 incorporated cities, including Richmond in the west, Oakley in the northeast, and Concord in the middle.

Contra Costa County Superior Court

Association of Bay Area Governments (ABAG)


1970 -558,389
1980 - 656,331
1990 - 803,732
2000 - 948,816
2001 - 981,600

Other Facts & Figures:

Size: 733 Square miles
Mean Household Income: $79,000
Median home price: $275,000


As part of the San Francisco Bay metropolitan area, Contra Costa County extends from the northeastern shore of the bay about 50 miles east to San Joaquin County.  The border on the south and west is Alameda County. The northern border is Suisun and San Pablo Bays.  The county is surrounded on three sides by water and is dominated by Mt. Diablo in its middle.


Contra Costa County has a mild and generally dry climate.  In the winter, snow only falls at the top of Mt. Diablo and some of the higher foothills.  Very, very rarely, snow will fall in other areas.  Temperatures almost never go below freezing during the winter. Summers are not too hot with comfortable humidity.  Rainfall usually totals around 30 inches per year.


Contra Costa County was one of the original 27 counties in California when it was incorporated in 1850.  The county seat at the time of incorporation was Martinez. 


Waterways, such as the Carquinez Strait and the Sacramento-SanJoaquin Delta are within the county.  Antioch and Brentwood are in the center of the rich farming areas of the county.  Mount Diablo rise almost 4,000 feet above the surrounding areas.


Obtain a Birth Certificate _ go to the county website and click on birth certificates under forms center

RootsWeb page for Contra Costa County

Contra Costa County Genealogical Society
US GenWeb page for Contra Costa County


Contra Costa County Library
1750 Oak Park Blvd.
Pleasant Hill, CA 94523
Phone: 1-800-984-INFO
FAX: (925) 646-6461
Contact Us:

County Law Library
1020 Ward St., 1st floor
Martinez, CA
Information: (510) 374-3019
Hours: Monday through Friday, 8 a.m. to 5 p.m. Information: (925) 646-2783. 100 37th St., Room 216, Richmond Hours: 8 a.m. to 5 p.m.


Contra Costa County Office of Education
77 Santa Barbara Road
Pleasant Hill, California 94523
Phone: 925.942.3388

Organizations & Groups:

Hispanic Chamber of Commerce
Contra Costa County
77 Santa Barbara Road
Pleasant Hill, California 94523
Phone: 925.942.3388

Contra Costa Convention & Visitors Bureau
1333 Willow Pass Road, Suite 204
Concord, CA 94520
Phone: 925-685-1184
Fax: 925-685-8190

Attractions & Other Information:

San Francisco Bay Area Transit Information

Contra Costa County Fairgrounds
1201 W. 10th St.
Antioch, CA
Phone: 925-757-4400
Held each year in Late May-Early June

Mt Diablo State Park
96 Mitchell Canyon Road
Clayton CA 94517

Blackhawk Automotive Museum
3700 Blackhawk Plaza Circle
Danville, CA 94506
Phone: 925-736-2277

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This page was last updated on 27 March 2009 at 10:13 pm