3.5 mile loop through grassland and chaparral, at a preserve which was a
former coal mine.
Distance, category, and difficulty:
This 3.5 mile loop hike is on the moderate side of easy. Trailhead
elevation is about 740 feet. The featured hike climbs to about 1250 feet,
then descends back to the trailhead. Total elevation change is about 700
Mostly exposed, with some shade.
Dirt fire roads and trails.
Too hot in summer. Best in late winter and early spring.
From CA 4 in Contra Costa County exit Somersville Road (exit 26a
eastbound/26 westbound). Drive south on Somersville to the park entrance.
If you're driving from San Francisco, or the south bay, these directions
may make your trip quicker (or at least more pleasant): from the CA 24/Interstate
680 interchange in Contra Costa County, exit Ygnacio Valley Road (exit 46b).
Drive east on Ygnacio Valley Road about 8 miles, then the road changes into
Kirker Pass. Continue about 5 miles on Kirker Pass to the junction with
Buchanan. Turn right and drive about 3 miles to Somersville Road. Turn right
and drive to the park entrance.
Get driving or public transit directions from Transit and Trails:
GPS Coordinates* for Trailhead:
(* based on Google Earth
data, shown as degrees, minutes, seconds)
Gas, food, and lodging:
Gas, stores, and restaurants back on Buchanan. Camping info from EBRPD:
"There are two camping areas in Black Diamond Mines Regional Preserve.
Reservations are required for both--call (510) 562-2267. Neither camping
area has water, so water must be transported in. Star Mine Group Camp Area,
available during spring, summer and fall, is for organized, educational
groups only. It can accommodate up to 40 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. 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
(not for human consumption). The camp is located 3.2 miles from the Preserve
headquarters, near the Stewartville and Upper Oil Canyon trails."
Once inside the park, you can stop at the park office for a map or help
with planning a hike. Then get back into your car and drive to the trailhead
at the end of the road. Entrance fee of $5 charged when entrance kiosk is
staffed. $2 dog fee. Drinking water, maps, and pit toilets at trailhead.
Large parking lot. Emergency phone at park office. There is a designated
handicapped parking spot, but trails aren't wheelchair accessible. There
is no direct public transportation to the park, but you can walk (or cycle)
to the trailhead from the Tri Delta Transit route 390 bus stop: visit the
Tri Delta Transit
website for details.
Most trails are open to hikers, equestrians, and cyclists, but a few trails
are designated hiking-only. Dogs are permitted. Park is open from 8 a.m.
The Official Story:
Black Diamond Mines page.
Park headquarters 925-757-2620
A slight variation
of this hike is described and mapped in 60 Hikes within 60 Miles: San
Francisco, by Jane Huber (yup, that's me, the creator of this website). Order
this book from Amazon.com.
Afoot and Afield: San Francisco Bay Area, by David Weintraub
this book from Amazon.com) has a great map and descriptions of a Black
Diamond Mines hike.
David Weintraub's East Bay Trails has a good map and descriptions
of 3 Black Diamond Mines hikes (order
this book from Amazon.com).
of Northern California, by Robin C. Johnson and Dot Lofstrom (order
this book from Amazon.com) has a nice geological description of this
View photos from the featured
Go to Bay Area Hiker Home page
Diamond Mines Regional Park was, once
upon a time, ranch land like much of the east bay (of course, before that
it was populated with Native Americans). When in the 1860s coal was discovered
at this parcel of land just south of Pittsburg, extensive mining took
place, with nearly 4 million tons of "black diamond" removed
from the earth. When coal use dropped off around the turn of the century,
the land was mined for sand. More than 1.8 million tons of the stuff was
removed. In spite of all that has been taken away, Black Diamond Mines
is remarkable for what remains. An over 5,000 acre park, Black Diamond
Mines boosts 65 miles of trails through grassland, chaparral, and oak
savannah, and past sandstone rock formations. If one day at Black Diamond
Mines isn't enough, a backpack and separate group camp make it possible
to linger a little longer.
Spring is the optimal time of year for a
visit, although the blue oaks are lovely in autumn, and the manzanitas are
stunning in winter. Springtime brings carpets of flowers, fresh oak leaves,
and soft warm temperatures. If you wish to learn more about the mining
history of Black Diamond Mines, you can stop by the Underground Mining
Museum, and/or hike to the remains of the mines. Most mine entrances are
barred, but bring a flashlight to explore 200 feet of Prospect Tunnel's
400-foot passage. If you're just interested in the trails, you'll have
plenty to choose from. Short loops originate at the main trailhead, as
well as the park office trailhead, and the entrance at Contra Loma Regional
Park. Longer hikes of 8-10 miles are possible as well. If you visit once
and are hooked like me, you'll have lots of map fun planning your next
hike at Black Diamond Mines.
Start at the gate near the information
signboard at the end of the parking lot. Walk uphill on the broad multi-use
Nortonville Trail.At about 250 feet, the trail crests at a signed junction. Turn left
on Stewartville Trail, open to hikers, equestrians, and cyclists.
A few steps later, at about 0.16 mile, you'll reach a signed junction
with Railroad Bed Trail. Continue straight on Stewartville Trail.
The grade is initially level, but after passing a junction with the Pittsburg
Mine Trail, Stewartville Trail begins to climb. The trailside grassland
hosts owl's clover, fiddlenecks, and ithuriel's spear in spring. At about
0.55 mile, Stewartville Trail attains its peak elevation and reaches a
signed junction just before a cattle gate. Turn right on Ridge Trail.
Ridge Trail starts out open to equestrians,
cyclists, and hikers, but a sign warns that there's no outlet for horses
and bikes ahead, as the trail enters a sensitive ecological area where
only hikers are permitted. There are nice views down into the valley to
the southeast, and a peak at Mount Diablo to the west. Ridge Trail climbs for a few feet, then dips down and contours
levelly around a hill. If you're hiking in late winter, you'll likely
see Padre's shooting stars nestled in the grass. Later in spring, lupines,
buttercups, and fiddlenecks are plentiful. Buckeyes and blue oaks pepper
the hillsides. On the left of the trail, look for the delicate white blossoms
of woodland star in spring. On a clear day, views unfold to the right,
permitting you to see all the way past the bay to Solano County. Ridge
Trail begin to climb, and passes through a cattle gate. Look on the left
for lots of bluedicks and a few owl's clover in early spring. Continuing
to ascend, you might notice a change in the trailside vegetation. Oaks
are still present, but the manzanitas seem out of place. And these aren't
stunted shrubs, but full-size and even tree-size specimens. This shift
in vegetation continues, and you'll reach a hilltop, at about 1195 feet,
with more manzanitas and coulter pines. Also look for yerba santa and stunning red paintbrush blooming in early spring.
On the left, a bare sandstone ledge provides the perfect rest stop. The
view down into the valley is just incredible. This has to be one of my
favorite bay area vistas. A verdant valley is dotted with ponds, and sheltered
on both sides by hills. Chaparral lines the slopes on the west, while
the eastern hills are shaded by oaks. A longer view to the west reveals
the high peaks of Mount Diablo. When I visited on a breezy spring day,
the winds rustled through the coulter pines, and I felt very far area
from the bay area. When you're ready, continue on Ridge Trail, which begins
to descend. The flowers of winter's Indian warrior give way to the cheerful
yellow blossoms of bush poppy as spring rolls around. Ridge Trail curves
to the left away from a dropoff, revealing sandstone rock formations down
the hill. At 1.25 miles, Ridge Trail ends at a signed junction. Turn
right on Chaparral Loop Trail. (Option: if you want to avoid a descent
followed by an ascent, and the crowds around the park's mining museum, you can continue straight at this
junction, on Chaparral Loop. The mileage will be about the same, but you'll
save yourself some energy.)
Sandstone soil, fostering coulter pines,
chamise, and manzanita, make this area of the park distinctive. Chaparral
Loop Trail, a hiking only path, descends gently toward a rock formation.
Paintbrush and bush poppy add color to the bare ground. At 1.32 miles,
you'll reach a signed junction in front of the rock formation (as far
as I know it is nameless, though it certainly deserves a great moniker).
Bear left on Lower Chaparral Trail.
Lower Chaparral Trail is also closed to
cyclists and horses. The sandy path loses elevation at an easy pace, then
narrows and drops somewhat steeply through a very rocky stretch. After
passing a path breaking off to the right (not a sanctioned route), Lower
Chaparral Trail edges across a grassy hillside. Look on the left for royal
larkspur, woodland star, and branched phacelia. Poison oak, which had
been absent until this part of the hike, makes an appearance. Lower Chaparral
Trail darts into the shade of coulter pines
and manzanita, and ends at a signed junction at 1.59 miles. Bear left
on Chaparral Loop.
Hiking-only Chaparral Loop climbs on a narrow
path through coulter pine, oaks, and manzanita. You'll pass rough paths
that ascend to join Chaparral Loop from the creekbed on the right. At
1.89 miles, Chaparral Loop Trail meets a signed junction. Bear right
(sign reads "to Manhattan Canyon Trail"). After climbing a few
feet, you'll reach another junction, with Manhattan Canyon Trail. Turn
Buckbrush and chamise line the hiking only
trail as it climbs. Look to the right, across the canyon, for views of
more rock formations barely concealed by vegetation. At 1.96 miles, there
is yet another junction. Manhattan Canyon Trail continues to the right,
but turn left, "to Black Diamond Trail." (By the way,
the last three junctions are really hard to follow with the park's map.
It's worthwhile to write down these directions, or at least be prepared
to roll with the punches if you find yourself off course.)
hiking only trail skirts the base of a natural rock wall, through chamise,
yerba Santa, sagebrush, and black sage. In spring you may see mosquito
bills blooming in the shade on the right side of the trail, and fremont's
camas tucked under the shrubs. There are nice views back across the canyon
to the southeast, and you may even catch a glimpse of some steps on Chaparral
Loop Trail. At 2.16 miles, the path ends at a signed junction with Black
Diamond Trail. Turn right.
After a short steep climb on multi-use Black
Diamond Trail you'll leave chaparral behind, and enter a lovely oak savannah.
In spring, look for carpets of bluedicks (they blend into the grass, so
they aren't all that obvious considering their numbers). Black Diamond
Trail levels out at a gate, and continues on a mostly flat course. There
are long views, encompassing the journey so far, and through a notch near
Rose Hill to the bay. If you're hiking in late winter, look to the right for
a staggering display of Padre's shooting stars. These white flowers really
stand out in the green grass. Black Diamond Trail begins to descend, passing
under power lines and ending at a signed junction at 2.69 miles. Bear
right onto Nortonville Trail.
Nortonville Trail, open to hikers, equestrians,
and cyclists, descends through grassland. Look for owl's clover, redmaids,
and lupines in the spring. A path to the left departs to visit Rose Hill
Cemetery, an optional side trip. At 3.17 miles, you'll reach a signed
junction with one of the legs of Manhattan Canyon Trail. Continue straight.
Nortonville Trail passes through a cattle gate, and at 3.31 miles, encounters
the second leg of Manhattan Canyon Trail. Continue straight.
Red winged blackbirds are plentiful especially
on the left side of the trail in a marshy area. Descending at a gentle
pace, the trail reaches a signed junction at 3.41 miles, with the most
commonly visited area of the park, the Underground Mining Museum (another
optional side trip). Continue straight on Nortonville Trail, under
a few blue oaks, past the previously encountered junction with Stewardville
Trail, and return to the trailhead.
Total distance: 3.5 miles
Last hiked: Tuesday, March 27, 2001