Contra Costa County is in San Francisco Bay Area California. Of the 58 counties in the Golden State, 514,601-acre Contra Costa County ranks 50th by size. The most common type of land for sale by combined acreage in Contra Costa County is residential property. Browse all waterfront property for sale in Contra Costa County on the Land Network to find the marina, lakefront and other recreational property that meets your needs, from waterside land perfect as a retirement investment to existing residential waterfront land and property for hunting, fishing and other outdoor-recreation pursuits!