Bay Nature

3814 acre Park managed by: East Bay Regional Park District

At this preserve you can hike the extensive trail network above ground, or learn about the historic coal and sand mining that occurred here underground in the 19th and 20th centuries.

The large park has a unique history. It was one of California’s largest coal mining areas between the 1860s and the early 1900s and supported five towns in the vicinity. Then in the 1920s the area was mined for sand which supplied a glass factory in Oakland and a steel factory with casting sand until 1949. An old cemetery and the remnants of the old mines are still visible. Guided history and natural history tours are available. The Greathouse Visitor Center is located in an underground chamber which was excavated as part of the sand mining operation.

Forty-two miles of trails wander through grassland, foothill woodland, mixed evergreen forest, and chaparral.There are two campgrounds areas in Black Diamond Mines Regional Preserve, one is for educational groups only, and the second for the general public.