Great Hikes: Hike the Black Diamond Mines Regional Preserve near Antioch

Published: Thursday, Nov. 11, 2010 - 12:00 am | Page 1D
Last Modified: Wednesday, Oct. 3, 2012 - 6:39 am

There will be moments among the rolling hills, the blue oaks, dry brush, deep red manzanitas and the ghostly remains of century-old mining towns when you'll stop and wonder: Wait, where am I again?

The answer is a six-mile hike through the Black Diamond Mines Regional Preserve south of Antioch.

Yes, Antioch, 65 miles southwest of Sacramento.

The road into the park first splits a shopping center – Planet Tan on your left, car repair on your right. Most of the traffic along that road turns off at James Donlon Boulevard, into the housing developments on either side.

But just past the James Donlon intersection on Somersville Road, the street narrows and turns to dirt, the houses disappear, and you become surrounded by pure hillsides for as far as you can see.

"As people come in," said Jesse Gonzalez, the park ranger who staffs the visitors center, "it feels like they're going back in time."

Once, this park was the site of the biggest coal mining operation in California. From the 1850s to the early 1900s, inhabitants of the five coal mining towns in the area removed nearly 4 million tons of coal (or "black diamonds") from the earth. As many as 900 miners joined the operation – making it the population center of Contra Costa County at the time.

Now it's a little-known East Bay park with 65 miles of trails – so little-known that many locals, including those who take James Donlon Boulevard home each day, aren't aware that it exists.

"People have told me, 'I've been driving by for years,' and they just never went straight," Gonzalez said.

"They're kind of shocked that it's even here."

The mining towns are long gone, but vestiges remain – a hillside cemetery, exotic trees, old mine shafts, crumbling structures of brick. They rest in a diverse landscape of grassland, woodland, evergreen forest and chaparral.

Follow Somersville Road into the park, past the kiosk (free if it's not staffed that day), and into a spacious parking lot about a mile past the visitors center. Start up the Somersville Trail, passing the Stewartsville Trail on your left, and join the Nortonville Trail, bearing right at a fork and heading uphill toward the Rose Hill Cemetery.

Most of the trails on this six-mile loop are fire roads – wide and clearly marked. Brown posts announce any merging or diverging of walkways, and maps are provided at the trailhead. Pick your day carefully – the hike is nicest in cool weather, as there's little overhead to shield you from the sun, but rain can turn the dirt trails to sloshy mud.

About a half-mile up the Nortonville Trail, take a quick detour to the cemetery, a Protestant burial ground for those who died in the mining district. Many of those buried here died before the turn of the century from mining accidents, scarlet fever or smallpox. The headstones are cut from white marble and feature names such as Theophile Dumas, Gwelym Humphreys and Lupyester Pritchard.

Continuing uphill, you reach the Nortonville Pass and look down into the valley that was once the site of the largest town in the Mount Diablo coal field. A lonely marker announces that Nortonville once sat on this spot. Hills rise up in all directions to meet the sky, like sides of a bowl. There is no water. Still, when Nortonville did exist, it must have felt like its own world.

You reach a T junction and turn left, joining the Black Diamond Trail. It soon becomes a paved road that you'll follow for several miles. You pass the Black Diamond Mine Shaft on the right, now dilapidated brick. You pass Jim's Place on the left, a cozy shelter that somebody carved out of a rocky hill, complete with a skylight and stovepipe hole.

Oaks reach over the trail as you continue up a series of steep S-curves. All at once you emerge from that cover, nearly at the hilltop. Turn around and there's the view.

It's a sweeping look over the Oakland and Berkeley hills, parts of Antioch and Oakley. City buildings glint far away. To your right, blue water and sky are separated by long fingers of orange land. The Highway 160 bridge into Antioch looks like a toy, and stiff winds blow in from the water with almost nothing to block them at these heights. It's a reminder of where you are – and when you are.

A dirt path splits off to the left and you'll follow it to start descending. On this side of the hill the long grass is at first a thirsty brown and windswept. Rustling animal noises carry across the quiet valley.

It doesn't stay like that for long. The surroundings take you through a heavily wooded area, then an Old West-type trail, sandy and surrounded by dry brush.

Partly for this reason, this loop is one of the most popular hikes in the park, said Jesse Gonzalez.

"You get a look at what the whole park has to offer," Gonzalez said.

The whole park spans nearly 6,000 acres. It includes mine shafts that are still open and can be toured. It offers guided walks, group and backpacking camps and trails that are mostly accessible to bicycles. It's open to animals. Recently, a park ranger led a group of poodles on a hike so they could experience some new terrain, Gonzalez said.

To finish your hike, continue on the Black Diamond Trail until you return to Nortonville Pass, and retrace your steps down the Nortonville Trail to the parking lot. Or you can break from the beaten path, leaving the Black Diamond route for the Manhattan Canyon Trail to the right around the four-mile mark.

This route is narrow and more dense, and after a few hundred feet you come to a small clearing that feels like a forgotten place. It overlooks a shallow valley of overgrown grass, and across the way is an old wire fence that divides somebody's land from somebody else's and looks like it hasn't been touched in years.

Dark red manzanitas line this route. You continue left at a fork to join the Chaparral Loop. It will lead you back to the parking lot and to your car. Somersville Road takes you past the new houses on James Donlon, the tanning salon and the Double Dragon Chinese restaurant, back to the highway and the present.


Hike length: 6 miles

Elevation gain/loss: 1,450 feet

Difficulty: Moderate

Directions: From Sacramento, take Interstate 5 south and take Exit 485 toward Rio Vista. Take Highway 12 west to Highway 160. Take 160 south to Highway 4. Take Highway 4 west to Somersville Road; take Somersville south. Stay in the left lane as you pass Buchanan Road. Continue straight while the main road, now called James Donlon Boulevard, bends left. At 2.6 miles from Highway 4, you'll reach the entrance kiosk.

Basic route

• The trailhead is at the parking lot. Picnic tables, water and portable toilets are available.

• Head south on Somersville Road, passing the Stewartville Trail on the left, and join the Nortonville Trail.

• After descending into the valley where Nortonville once was, you come to a T-junction and the end of the Nortonville Trail. Turn left onto Black Diamond Trail. Continue to a junction with the paved Black Diamond Way.

• Climb on a moderate grade to an open ridgetop. At a junction with a wide dirt road on the left, follow the dirt road to continue on the Black Diamond Trail.

• Around four miles, veer right onto Manhattan Canyon Trail.

• At a Y-junction with a foot bridge on the right, go left to join Chaparral Loop Trail. Follow Chaparral Loop until you reach a long flight of stairs. Descend, and follow trail back to the parking lot.

For a shorter route

At junction to Manhattan Canyon Trail, continue on Black Diamond Trail. At another connector to the Manhattan Canyon Trail, continue straight and take Black Diamond Trail back to Nortonville Pass. Turn right onto Nortonville Trail and follow it back to parking lot.

Probability of getting lost: Low (many signposts)


Great Treks and its companion, Great Rides, are Outbound features that invite readers to enjoy the region's outdoors by bicycle and on foot. Have a suggestion for a route or another kind of great outdoors experience? Send an e-mail to

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Read more articles by Matt Kawahara

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