The mission of the California Department of Parks
and Recreation is to provide for the health, inspiration and education of the people of California
by helping to preserve the state’s extraordinary
biological diversity, protecting its most valued
natural and cultural resources, and creating opportunities for high-quality outdoor recreation.
Secretary for Resources
Director, California State Parks
California State Parks does not discriminate against
individuals with disabilities. Prior to arrival, visitors
with disabilities who need assistance should contact
the park at the phone number below. To receive this
publication in an alternate format, write to the
Communications Office at the following address.
P. O. Box 942896
For information call:
916-653-6995, outside the U.S.
888-877-5379, without TTY
MOUNT DIABLO STATE PARK
96 Mitchell Canyon Road
Clayton, CA 94517
Cover photo by Stephen Joseph Photography,
© 2000 California State Parks (rev. 9/04)
t the eastern fringe of the San Francisco
Bay Region, Mount Diablo, elevation
3,849 feet, stands alone on the edge of
California’s great Central Valley. At this point,
the Coast Range consists only of low hills, none
high enough to block the view from the upper
slopes of the mountain. As a result, the view is
The View From the Top — Many visitors to
Mount Diablo head straight for the summit to
enjoy the famous view. Summer days are
sometimes hazy, and the best viewing is often
on the day after a winter storm. Then, you can
look to the west, beyond the Golden Gate
Bridge, to the Farallon Islands; southeast to the
James Lick Observatory on Mount Hamilton at
4,213 feet elevation; south to Mount Loma Prieta
in the Santa Cruz Mountains at 3,791 feet elevation; north to Mount Saint Helena in the Coast
Range at 4,344 feet, and still farther north to
Mount Lassen in the Cascades at 10,466 feet.
North and east of Mount Diablo, the San Joaquin
and Sacramento Rivers meet to form the twisting
waterways of the Delta. To the east beyond
California’s great Central Valley, the crest of the
Sierra Nevada seems to float in space. With
binoculars, you may even be able to pick out
Half Dome in Yosemite National Park.
Mount Diablo is a sacred mountain to California
Indian people. Just about every California Indian
community who viewed Mount Diablo would, at
one time or another, make a pilgrimage to the
summit area for ceremonies. The reason Mount
Diablo is so sacred to the California Indian
people is that it was the creation point for the
Miwok people or genesis for some California
In 1851, the mountaintop was selected as the
starting point for a survey of the public domain.
Ignoring the excitement of the Gold Rush,
Leander Ransom and his men erected a flagpole
at the summit of Mount Diablo and began to
extend the base and meridian lines that we use
to this day in our official land surveys. As a
matter of fact, Mount Diablo base and meridian
lines are referred to in legal descriptions of real
estate throughout two-thirds of California and
parts of Nevada and Oregon.
Toll roads up the mountain were opened in
1874, and for many years there were two stages
every day connecting Walnut Creek and Danville
with Mountain House, a 16-room hotel about
three miles from the summit. The Stage Road,
near Pine Canyon, was one of the original stagecoach line routes. The hotel offered all conveniences and was known for its excellent food.
Wedding ceremonies were a frequent occurrence at the hotel, and celebrities from all over
Europe and America were among the visitors. In
those days, it was widely held that you hadn’t
seen the West if you hadn’t watched a sunset,
sunrise, or full moon from the upper slopes of
Business at the hotel declined after the
summit observation platform burned in 1891,
and shortly thereafter the hotel burned down as
well. The toll roads were reopened in 1915, so
that the view from the summit was once again
available to all.
In 1921, a parcel of land on the mountain was
designated a state park, and much of the rest of
the mountain was declared a game refuge.
Standard Oil placed a ten-million-candlepower
aerial navigation beacon on the summit in 1928.
ABOVE: In 1935 the transbay ferries were still running, the Bay Bridge was nearing completion, and San Francisco itself was
rapidly assuming its modern appearance. Then, as now, Mount Diablo rose above it all, serene and aloof, majestically
dominating the eastern horizon. BELOW: View of Castle Rock from Shell Ridge.
The beacon was so powerful that it could be
seen by ships 100 miles at sea. Finally, in 1931,
the state acquired more land for Mount Diablo
State Park, and the park was formally dedicated
and opened to the public.
Much of the rock that makes up Mount Diablo is
sedimentary in origin. It was laid down millions
of years ago on the floor of the ocean. Within the
last one to two million years, a piece of hard, red
160-million-year-old Franciscan rock was pushed
up through six to eight miles of overlying rock
and soil, tilting and
distorting the rock layers
and in some places
turning them completely
upside down. As a
result, the fossilized
remains of many sea
creatures, as well as
those of mastodons,
saber-toothed cats and
three-toe horses have
been discovered here.
Elevations in the park
range from 300 to 3,849 feet. This wide range of
elevations creates broad variations in temperature, rainfall and wind exposure that have
resulted in a wide variety of plant life on the
mountain. Summers are hot and dry, so many
people prefer to visit in spring and fall. The
park is also popular in winter, when Bay Area
residents occasionally enjoy the unusual
experience of a snowfall on the mountain’s
Most of the park is typical central California
oak and grassland country with extensive
areas of chaparral. Riparian woodland occurs
on the lower slopes of the mountain, where
the streams have water in them throughout
most of the year. Several isolated stands of
knobcone pine occur within the park, and
foothill pine is found in many places. The
northernmost groves of coulter pine occur on
the lower, northerly slopes of the mountain,
near the old mining ghost towns of Nortonville
and Somersville just outside the park. Other
trees include the coast live oak, bigleaf maple,
California laurel (Oregon myrtle), maul oak, blue
oak and buckeye. In all, over 400 species of
plants have been identified within the park’s
almost 20,000 acres.
Wildlife is also abundant. Coastal blacktailed deer, raccoons,
squirrels, eastern fox
squirrels and gray foxes
are often seen, but
striped and spotted
skunks, bobcats, mountain lions, coyotes, deer mice, cottontail
rabbits, black-tailed hares and many other
animals call the mountain home. Mount
Diablo is known to harbor red-legged frogs,
tarantulas, and the rare Alameda whipsnake, as
well as its cousin the northern rattlesnake.
POINTS OF INTEREST
Summit Building and Museum — Constructed
in the late 1930s by the California Conservation Corps, the sandstone for the building was
quarried from Rock City. Remnants of ancient
fossils can be found on the building.
Unusual snowfall covers the Summit Building.
The Fire Interpretive Trail — Just below the
summit, this trail showcases the natural recovery process that is underway following a 6,000acre fire in 1977. Some spectacular vistas can
be enjoyed along the way. The first half of this
gentle 0.7-mile trail is accessible to visitors in
Rock City — You will find unusually large
sandstone formations and small caves here.
Climbing Rocks and Castle Rock — These are
popular places for rock climbing. Check with
the ranger for regulations and the best approach.
Fossil Ridge — Evidence of previous residents
is embedded in these rocks. Please leave
them for future visitors to see.
Macedo Ranch — An excellent staging area for
horseriders, bicyclists and hikers, located on
the western side of the park.
Deer Flat — You are likely to see some of the
mountain’s natural wildlife as you take this
moderately strenuous 1.6-mile hike from
Mitchell Canyon Staging Area — This is the
main access point to trails on the mountain’s
north side. From here you can hike to Deer
Flat (3.7 miles)
or all the way to
the summit (6.8
miles) by way of
Center is open on weekends from 8:00 a.m to
Diablo Valley Overlook — From here, 2,900
feet above sea level, you can see the Golden
Guided hikes and other interpretive events
are conducted by the park staff. Publications
of the park’s history and natural history and a
detailed topographic hiking map are for sale in
the park office, at entrance stations and at the
Summit, where knowledgeable docents are
available to answer your questions. The
summit museum is open Wednesday through
Sunday, 10:00 a.m.-4:00 p.m., November
through February and 11:00 a.m.-5:00 p.m.,
April through October.
There are more than 50 picnic sites, each with
table and barbeque stove, scattered along the
park’s paved roads. There are also three group
picnic areas that can accommodate from 25 to
100 people each. They can be reserved
through park headquarters.
Mt. Diablo has 56 campsites with hot showers
and flush toilets. Some sites will accommodate RVs up to 20 feet; trailers are not
recommended due to road conditions.
Group sites are available with running
water and pit toilets. Some have horse
Campsite reservations can be made by
phone up to seven months or as little as 48
hours in advance by calling (800)444-7275.
Outside of the United States, call (916) 6385883. Reservation fees can be charged to
VISA®, Discover® Card or MasterCard®.
Group camping reservations can be made up to
seven months in advance.
A NOTE FOR BICYCLISTS
Mountain bikes may be ridden on paved
roads, maintained fire roads and authorized
trails. The three trails currently open to
mountain bikes are:
• Summit Trail from South Gate Road through
Dan Cook Canyon.
• Mother’s Trail from Angel Kerley Road to the
connector trail to Burma Road.
• North Peak Trail from Summit Road at
Devil’s Elbow to Prospector’s Gap.
Cyclists should see park staff for other rules
and regulations concerning trail use.
Mt. Diablo Interpretive Association is a nonprofit
organization devoted to the promotion of interpretive, scientific and educational projects to help the
general public enjoy and become knowledgeable
about Mt. Diablo, a unique mountain island within
an ever-encroaching urban development.
• Alcoholic beverages are NOT allowed in the
• Dogs are allowed only in developed areas in
the park. They must be kept on a leash
during the day and in an enclosed vehicle or
tent at night. Dogs are NOT permitted on
trails or fire roads.
• Fires are a continuing hazard; weather conditions may restrict smoking or prohibit fires or
even close the park during periods of extreme
fire danger. See park staff for specific information. Fires are only allowed in the park’s
barbeques or your portable camp stove.
Bring your own fuel. Collection of firewood is
prohibited in the park.
• Poison oak is found throughout the park. It
can cause an unpleasant rash that can even
be transmitted by touching clothing that has
brushed against the plant. Stay on the trails
and avoid this hazard.
• Plants and animals – even rattlesnakes – are
protected by law. This is their home, and you
are the visitor. To avoid rattlers, watch where
you are hiking, and if you see one, give it a
wide berth. It is no more anxious for an
encounter than you are.
• Park hours are 8:00 a.m. to sunset daily. Gates
close at sunset and are locked at night.
Mt. Diablo Interpretive Association
P.O. Box 346
Walnut Creek, CA 94597-0346
NIPER T R
S y camore
CAM I N O
O UTH G
FIRE ROADS (HIKING BUT NO VEHICLES)
POINT OF INTEREST
GE L RI
C re e k
SUM M IT
RT K )
Mt. Diablo Summit
M O RGAN
FIRE INTERPRETIVE TRAIL
AN G E L
Poison oak can be
identified by its leaves;
they grow in groups of
three and have gently
Ticks are found on
Mt. Diablo. Check
yourself and your
(Not actual size)
P in e
I T CHE
M IT C H E
North Gate Entrance
& Ranger Station
S TAT E PA R K
M I T CHELL C
AN Y ON RD.
Most land adjacent to the park is private property.
No trespassing without owner's permission.