The Black Diamond Railroad Trail is within the Black Diamond Mines Regional Preserve, a splendid place to visit with a fascinating and unique history. From the 1850s to the early 1900s, the region was the site of the largest coal mining operation in California. People from all over the world migrated here, and the coalfield's presence transformed the area from one primarily used for cattle ranching into the industrial and population center of Contra Costa County. Mining operations ceased in the late 1940s because of dwindling profits, and the land reverted to agricultural use once again.
In the late 1970s the East Bay Regional Park District started to acquire the property to create the Black Diamond Mines Regional Preserve. Today, the preserve totals nearly 6,000 acres, supports a diverse wildlife population, offers visitors a variety of activities and is a primary destination for Bay Area nature-lovers. Some of the fascinating sites that can be explored here include original mine openings, a cemetery and a visitor center, which contains displays, photographs, videos, brochures and artifacts depicting the park's mining eras.
The preserve contains some 65 miles of trails. One of these, the Black Diamond Railroad Trail, is a short rail-trail that can be explored by bicycle or on foot. Its length and slight incline makes it ideal for people of all ages. There is no shade along the trail, though, so be sure to bring plenty of water and protection from the sun. The trailhead is located at the south end of the main parking lot, where there are restrooms, water fountains and literature about the preserve and its history.
Once you step onto the rail-trail, you are surrounded by the expansive Mt. Diablo foothills. On the left is a steep canyon covered with lush green grass and bright yellow wildflowers in spring. On the right is a ravine and Somersville Road, which parallels the rail-trail its entire length. Look beyond the road for a vista of rolling hills, where cattle, rabbits and deer roam.
The canyon grows slightly narrower you ascend it. At the trail's end there is a rest area with picnic tables, restrooms and a small parking lot. It is the perfect place to sit down, have a snack and enjoy the peaceful surroundings. You can turn around or continue hiking on the unpaved trails of various lengths that branch out from this point.
Parking and Trail Access
To reach the northern trailhead, take State Route 4 to the Somersville Road Exit in Antioch, then drive south (toward the hills) on Somersville Road until it enters the Black Diamond Mines Regional Preserve. Continue another mile or so to the park entrance station and park in the lot. The trailhead is at the south end of the main parking lot.
To reach the southern trailhead, continue on Sommersville Road past the visitor center for another mile, and you will come to a small parking lot. You can park in here to access the rail-trail from the south end.