5175 Somersville Road
Antioch, CA 94509
Parking: Seasonal, weekends and some holidays (Visa/Master Card, cash or check only): $5 per vehicle (when the kiosk is attended); $4 per trailered vehicle. Buses: $25/per bus.
Dogs: $2 per dog. Guide/service dogs free.
Jan 1-29: 8am-5pm
Jan 30-Mar 13: 8am-6pm
Mar 14-Apr 11: 8am-7pm
Apr 12-Sep 6: 8am-8pm
Sep 7-Nov 6: 8am-7pm
Nov 7-Dec 31: 8am-5pm
Sydney Flat Visitor Center
CLOSED until further notice
10am - 4:30pm, weekends,
December - February
Greathouse Visitor Center
- Fri.: 10am-2pm (Jul – Aug)
- Sat. & Sun.: 10am-4:30pm (Mar–Nov).
Toll Free: 888-EBPARKS (888-327-2757), option 3, extension 4506
Black Diamond Mines Main Entrance
> Park Map [PDF]
> Google Map
The East Bay Regional Park District began acquiring land for Black Diamond Mines Regional Preserve in the early 1970s. Today, most of the mining district is within the Preserve's nearly 8,533 acres. The area is an ideal location for hiking, picnicking and nature study. Naturalists conduct a variety of programs relating the Preserve's natural and historic resources. For information phone (510) 544-2750.
Native Americans have lived in the greater Bay Area for thousands of years. Black Diamond was located in the backcountry between three tribes: Chupcan (Concord), Volvon (Clayton) and Ompin (Pittsburg). All three nations spoke the Bay Miwok language. With the arrival of Spanish, Mexican and American settlers after 1772, the Bay Miwok way of life changed rapidly.
Until the discovery of coal, cattle ranching was the major industry in this area. After the mines closed, some miners found a new career in ranching. Abandoned mining town buildings became barns, railroad ties were used as fence posts, and boilers were converted into water troughs. Descendants of original mining families still graze cattle in the Preserve.
From the 1860s through the turn of the last century, five coal mining towns thrived in the Black Diamond area: Nortonville, Somersville, Stewartville, West Hartley, and Judsonville. As the location of California's largest coal mining operation, nearly four million tons of coal ("black diamonds") were removed from the earth. The residents of the mining towns were from all over the world, and their life was characterized by hard work and long hours. Occasional celebrations and a variety of organizations and social activities served to alleviate the drudgery of daily existence.
The coal mines had a significant impact on California's economy. By the time operations ceased due to rising production costs and the exploitation of new energy sources, much of California's economy had been transformed from a rural to an industrial base.
In the 1920s underground mining for sand began near the deserted Nortonville and Somersville townsites. The Somersville mine supplied sand used in glass making by the Hazel-Atlas Glass Company in Oakland, while the Nortonville mine supplied the Columbia Steel Works with foundry (casting) sand. Competition from Belgian glass and the closing of the steel foundry ended the sand mining by 1949. Altogether, more than 1.8 million tons of sand had been mined.
Although little remains of the coal mining communities, a historic cemetery serves as a monument to the lives of the former residents. Buried here are children who died in epidemics, women who died in childbirth, and men who died in mining disasters and of other things. Although over 10 nationalities resided in the mining area, Rose Hill Cemetery was a Protestant burial ground, and many of the people buried here were Welsh.
Over the years, vandalism has taken its toll on the cemetery, which the Park District is attempting to restore. If you have information concerning people buried here or the location of missing gravestones, please call the Black Diamond office at (510) 544-2750.
Please note: Sydney Flat Visitor Center will be CLOSED until further notice.
Behold remnants of the past and peruse the wonders of the park in a building original to the coalfield. The Sydney Flat Visitor Center contains displays of photographs and artifacts from the 1800s and early 1900s.
Admission is free. Parking fee is $5 per vehicle on weekends and holidays (Visa/Master Card, cash or check only). For more information, or to ask about visiting Sydney Flat Visitor Center during the week, please call (510) 544-2750.
Hours: Friday 10am-2pm (July – August) and Saturday & Sunday 10am-4:30pm (March – November).
The Greathouse Visitor Center is located in an underground chamber excavated in the mid-1920s. View the workings of a 20th-century sand mine and learn about the lives of 19th-century coal and 20th-century sand miners. The center contains displays, photographs, and artifacts related to the park’s coal and sand mining eras.
Admission is free. Parking fee is $5 per vehicle on weekends and holidays (Visa/Master Card, cash or check only). For more information, call (510) 544-2750.
From the mid-1920s to the mid-1940s, the Hazel-Atlas Mine produced silica sand to make jars, bottles, and other glass items. Today, tour participants can take a 1309-foot walk into the mine to see mine workings, ore chutes, the shifter's office, and ancient geological features. For safety reasons, you may tour the mine only as part of a guided tour and all participants must be at least seven years old.
Vegetation: The Preserve's 65 miles of trails traverse areas of grassland, foothill woodland, mixed evergreen forest, chaparral, stream vegetation and exotic plantings. Notable among the latter are several tree species introduced by the coal miners. These include the black locust, pepper tree, almond, eucalyptus and tree of heaven.
Black Diamond is noted as the northernmost location of Coulter pine, black sage, desert olive, and dudleya. In addition, several species that are restricted to the Mt. Diablo area occur here, including the Mt. Diablo globe lily, Mt. Diablo helianthella and Mt. Diablo manzanita. In the springtime, the hills are covered with some of the most remarkable wildflower displays in the Bay Area.
Wildlife: Black Diamond supports a healthy wildlife population. Coyotes and snakes are commonly seen. Mountain lions, bobcats, foxes and deer are occasionally spotted, while birds of prey soar overhead. Over 100 species of birds have been seen, from the rare golden eagle to the ever-present meadowlark.
The side-blotched lizard has its northern limit in the Preserve, and one rare animal species has been found here, the Alameda whipsnake.
There are two camping areas in Black Diamond Mines Regional Preserve.
Reservations are required for both--call 1-888-EBPARKS (1-888-327-2757).
Star Mine Group Camp Area is available all year for organized, educational groups only. It can accommodate up to 35 people. It is located in a grassland/oak woodland community at the eastern edge of the Preserve. Overnight camping is limited to two nights. Parking (maximum eight cars), picnic tables and a pit toilet are available at the site. Campers must bring in their own water and haul out their own garbage. No water is available at the site. Camping reservations must be made at least ten (10) days in advance.
Stewartville Backpack Camp is for the general public. The fee is $5 per night per person. Camping is limited to two nights during the spring, summer, and fall. There is room for 20 campers. Picnic tables and a pit toilet are available, as well as water for horses (the water is non-potable and must be filtered or treated for human consumption). The camp is located 3.2 miles from the Preserve headquarters, near the Stewartville and Upper Oil Canyon trails. Camping reservations must be made at least five (5) days in advance.
Park naturalists provide a variety of programs relating to the preserve's natural and cultural history. For information on upcoming programs please call (510) 544-2750 or send an e-mail to firstname.lastname@example.org.
The Sydney Flat Visitor Center and the Interpretive Information Center are wheelchair accessible, as well as the restrooms and water fountain in the upper lot. Please call ahead (510) 544-2750 for assistance.
Black Diamond is located in Contra Costa County, south of Pittsburg and Antioch. Take Highway 4 to the Somersville Road exit in Antioch, then drive south (toward the hills) on Somersville Road to the Preserve entrance.
Transit & Trails: Black Diamond Mines / Contra Loma Regional Park
(Transit, biking, and walking directions)
Available from Black Diamond Visitor Center or Arcadia Publishing: Images of America - Black Diamond Mines Regional Preserve, an illustrated history of the Black Diamond Mines Regional Preserve published in 2009 and written by Supervising Naturalist Traci Parent and Black Diamond volunteer Karen Terhune.
Also available for purchase is Rose Hill - A Comprehensive History of a Pioneer Cemetery in the Mount Diablo Coal Field, written by Supervising Naturalist Traci Parent and published in 2011 by the East Bay Regional Park District. This nearly 1,200 page book is based on her 30 years of research into the history of the people buried in the pioneer cemetery at Black Diamond. The book can be purchased at the Black Diamond Mines Regional Preserve Visitor Center.
Click the map image below to see an enlarged version.