Black Diamond Mines: Clayton to Antioch
- Length: 10.6mi
- Travel time: approximately 1h13min from MacArthur BART
- Stop served: daily
- Google Maps:
- Park information
- Hike route
County Connection buses 10 (weekday) and 310 (weekend) serve the western trailhead. Transfer at Concord BART.
Tri Delta 380 serves the eastern trailhead. Transfer at Pittsburg/Bay Point BART.
Black Diamond Mines is perhaps my favorite part of the entire East Bay parks system. A few main valleys make up the bulk of it, with each possible hike taking you from one to the other across the ridges that separate them. This hike enters in Clayton a few blocks from Mt Diablo State Park’s Mitchell Canyon entrance, and takes you all the way to Antioch. Along the way you’ll pass closed off 20th century coal mines – black diamond – along with a 200ft long prospect tunnel you can explore, a crumbling cemetery, and Diablo, Carquinez, and Delta views.