Contra Costa County, CA Genweb Project a collection of online resources for genealogy researchers
Contra Costa County Historical Society has obituaries that appeared in Contra Costa Gazette 1855-1920 and a Probate database (select "research" from the menu)
Contra Costa County Message Board read and post messages with other genealogy researchers of this county
Contra County, CA Genealogy Forum read and post messages about your ancestors for this county
Contra Costa County Genealogical Society
The Tombstone Transcription Project - cemeteries for Contra Costa Co. CA
US GenWeb Archives for Contra Costa County cemeteries, newspapers, wills, military rosters etc recorded online
1876 and 1898 Voters Lists

Additional Resources

California Newspaper Search enter your California ancestor's name to instantly search the world's largest newspaper archive; over 12 million newspaper pages
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