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Guide to Contra Costa County, California ancestry, family history, and genealogy birth records, marriage records, death records, census records, family history, and military records.


Contra Costa County, California
Map of California highlighting Contra Costa County
Location in the state of California
Map of the U.S. highlighting California
Location of California in the U.S.
Founded 1850, February 18
County Seat Martinez
Address Contra Costa County
 730 Las Juntas St;
PO Box 350;
Martinez, CA 94553;
Phone. 925.646.2360
Contra Costa County Website


County Information

Contra Costa County, California Record Dates

Beginning Dates for Major County Records[1]
Birth Marriage Death Census Land Probate
1906 1906 1906 1850 1848 1850

County Courthouse

County Recorder has birth and death records; County Clerk
has marriage, divorce, probate and court records[2]

Historical Facts

Contra Costa County began in 1850 as one of the original counties in the new state of California. Located in the East Bay area, San Pablo Bay and Suisun Bay partially surround the land area of the county and have contributed to the economy since the gold rush. 

Wikipedia has more about this subject: Contra Costa County, California

Parent County

18 February 1850: Contra Costa County was created as an original county. County seat: Martinez [3]

Boundary Changes

For animated maps illustrating California county boundary changes, "Rotating Formation California County Boundary Maps" (1850-1925) may be viewed for free at the website.

Records Loss

For a list of record loss in California counties see: California Counties with Burned Courthouses


Populated Places

  • Antioch
  • Brentwood
  • Clayton
  • Concord
  • Danville
  • El Cerrito
  • Hercules
  • Lafayette
  • Martinez
  • Moraga
  • Oakley
  • Orinda
  • Pinole
  • Pittsburg
  • Pleasant Hill
  • Richmond
  • San Pablo
  • San Ramon
  • Walnut Creek

Neighboring Counties


Bible Records

Biography - Indexes




  • For tips on accessing Contra Costa County, California Genealogy census records online, see: California Census.

Church History and Records

Church records and the information they provide vary significantly depending on the denomination and the record keeper. They may contain information about members of the congregation, such as age, date of baptism, christening, or birth; marriage information and maiden names; and death date. For general information about California denominations, view the California Church Records wiki page.

Public Records

Court Records

Crime and Criminals


Ethnic, Political, or Religious Groups



A wiki article describing an online collecion is found at: California, Genealogical Collections at the California Genealogical Society (FamilySearch Historical Records)



Contra Costa Genealogical Society directory & Periodical


Local histories are available for Contra Costa County, California Genealogy. County histories may include biographies, church, school and government history, and military information. For more information about local histories, see the Wiki page section California Local Histories.



Land and Property & Maps

Land and property records can place an ancestor in a particular location, provide economic information, and reveal family relationships. Land records include: deeds, abstracts and indexes, mortgages, leases, grants and land patents.

See California Land and Property for additional information about early California land grants. After land was transferred to private ownership, subsequent transactions were usually recorded at the county courthouse and where records are currently housed.




Military History and Records

Naturalization and Citizenship

Newspapers and Indexes

Additional newspapers abstracts can sometimes be found using search phrases such as Contra Costa County, California Genealogy newspapers in online catalogs like:



Probate Records

The county clerk is usually the custodian of probate records. The records include wills, fee books, claim registers, legacy records, inheritance records, probate ticklers, and dockets.

Content: Probate Records may give the decedent's date of death, names of his or her spouse, children, parents, siblings, in-laws, neighbors, associates, relatives, and their place of residence.

You can obtain copies of the original probate records (such as wills and estate files) by writing to the county clerk at the county courthouse.

The FamilySearch Catalog lists films of probate records. To find the records for this county, use the Place Search for California - Contra Costa - Probate records.

Online Probate Records


Archives, Libraries and Museums

County Courthouse

Family History Centers

Family History Centers provide one-on-one assistance and free access to premium genealogical websites. In addition, many centers have free how-to genealogy classes. See Family History Center for more information. Search the online FHC directory for a nearby family history center.


San Ramon Valley Genealogical Society serves local genealogy enthusiasts. Monthly meetings are held at the Danville Family History Center in Alamo, California on the 3rd Tuesday at 10am.


California tax records complement land records and can supplement the years between censuses. There may be gaps of several years in the tax records of some counties. For more information, see the wiki page California Taxation.

Vital Records

Vital Records consist of births, adoptions, marriages, divorces, and deaths recorded on registers, certificates, and documents. See the CDC Where to Write website for information on acquiring copies of these records. The State office has records since July 1905. For earlier records, contact the County Recorder. See also How to order California Vital Records





  • Death records, 1873-1921
  • Contra Costa County maintains records of death certificates from 1905 to present. You can obtain an informational copy for a fee by mailing the Application for Death Record from the county clerk's website with your payment. As with other counties, you only need to get the form notarized if you want a certified copy. Informational copies do not need a notary.

Voting Registers

Genealogy Societies, Archives and Libraries

Antioch Historical Society
1500 W. 4th St.
Antioch, California 94509

Contra Costa County Genealogical Society
Concord/Walnut Creek Family History Center
3700 Concord Blvd
Concord, CA 94519-1808

Contra Costa County Historical Society
610 Main Street
Martinez, California 94553
Phone: 925-229-1042

East Contra Costa Historical Society and Museum
3890 Sellers Ave.
Brentwood, California 94513

El Cerito Historical Society
PO Box 304
El Cerrito, CA 94530

Lafayette Historical Society
Lafayette Library Learning Center
3491 Mount Diablo Boulevard
Lafayette, CA 94549
Phone: 925-283-1848

Martinez Historical Society
P.O. Box 14
Martinez, CA 94553
Phone: 925-228-8160

Moraga Historical Society
Post Office Box 103
1500 St. Mary's Rd.
Moraga, CA 94556-2099;
Phone: ( 925 ) 377-8734

Point Richmond History Society
139 1/2 Washington Avenue
Point Richmond, CA
Phone: 510-234-5334 or 510-235-1336

Richmond Museum of History
P.O. Box 1267
400 Nevin Avenue
Richmond, California 94802
Phone: (510) 235-7387

San Ramon Valley Genealogy Society
P.O. Box 305
Diablo, CA 94528-0305

Museum of the San Ramon Valley
P.O. Box 39
Danville, CA 94526
Phone: 925-837-3750

Walnut Creek Historical Society
2660 Ygnacio Valley Road
Walnut Creek, California
Phone: (925) 935-7871

Contra Costa County Genealogical Society
P.O. Box 910
Concord 94522

Contra Costa County Historical Society
P.O. Box 821
Pleasant Hill 94522

Costa Mesa Historical Society
P.O. Box 1764
Costa Mesa 92628

Web Sites

A wiki article describing this collection is found at:


  1. Alice Eichholz, Ancestry’s Red Book: American State, County and Town Sources, Revised ed. (Salt Lake City: Ancestry, 1992), 62-75. At various libraries (WorldCat); FHL Book 973 D27rb 1992
  2. Handybook for Genealogists: United States of America, 10th ed. (Draper, Utah: Everton Pub., 2002), Contra Costa County, California. Page 84 At various libraries (WorldCat); FHL Book 973 D27e 2002.
  3. The Handybook for Genealogists: United States of America,10th ed. (Draper, UT:Everton Publishers, 2002).


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  • This page was last modified on 20 November 2015, at 19:34.
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