Martinez is the county seat for Contra Costa County
Orinda is in Contra Costa County
Contra Costa County(480) ► ADJACENT TO CONTRA COSTA COUNTY Alameda County(674) ► Marin County(249) ► Sacramento County(392) ► San Francisco City and County(722) ► San Joaquin County(143) ► Solano County(114) ► Sonoma County(163) ►
Touch name on this list to highlight map location. Touch blue arrow, or on map, to go there.