Contra Costa County, California

Black Diamond Mines (Somersville) — Historic · Contra Costa County, CA
Heart of California’s largest 19th-century coal field, now inside East Bay Regional Park District’s Black Diamond Mines Regional Preserve. Somersville was on…
John Muir National Historic Site — Historic · Contra Costa County, CA
National Park Service unit in Martinez preserving the 1882–1914 home, orchards, and part of the fruit ranch of naturalist and conservationist John Muir — oft…
Point Richmond Historic District — Historic · Contra Costa County, CA
Point Richmond Historic District is a historic district in Contra Costa County, CA, listed on the National Register of Historic Places in 1979, recognized fo…
Port Costa — Historic · Contra Costa County, CA
Tiny historic Carquinez Strait waterfront town that boomed in the late 19th century as a grain-shipping and rail transfer port opposite Benicia. Brick wareho…