Approximate location — plotted from published sources, not a site visit, and not a guarantee of access.
Heart of California’s largest 19th-century coal field, now inside East Bay Regional Park District’s Black Diamond Mines Regional Preserve. Somersville was one of five coal towns (with Nortonville, Stewartville, West Hartley, Judsonville) that shipped nearly four million tons of “black diamonds.” Greathouse Visitor Center, Rose Hill Cemetery, interpreted townsites, and guided Coal Mine Experience programs present the industrial and immigrant history.