The devil’s peak’s history is as rich as its wildlife. With forests reaching to its summit and many unique flowering plants, it has been a reference point for local peoples for as long as they have lived here.

Name: Mount Diablo
Height: 1,173 m (3,849 ft)
Location: Diablo Range, Northern California, USA.
First Climbed: unknown
Climb Time: 3-12 hours
Best Time to Climb: April-October

INTRODUCTION TO MOUNT DIABLO.

What mysteries Mount Diablo holds we can only surmise, each of us needing to choose which of the mystical tales we wish to believe.

Jump to Hiking Guide.

Criss-crossed with hiking trails, multiple summits with distant views comparable only to Mount Kilimanjaro, and a road to the summit, this is a peak designed for accessible adventures. Whatever kind of Armchair Mountaineer you are, you’ll discover satisfaction on Mount Diablo (1,173 m/ 3,949 ft).

HISTORY OF MOUNT DIABLO.

This mountain’s human history and place in mythology is perhaps its most significant feature.

Mount Diablo’s importance begins with the local Native American peoples. In the mythology of two of them, the Sierra Miwok and the northern Ohlone, Mount Diablo was the point of creation. Both of these myths are believed to be over 4,000 years old.

According to the Sierra Miwok, there was once an epic flood and the first world people were forced up the slopes of Mount Diablo. When the waters receded, they went in search of food, but died when each sank into the waterlogged mud.

A raven landed on each hole into which a person had sunk, and these ravens transformed into the Miwok, the new world people.

In the northern Ohlone myth, the old world was destroyed, again by a great flood. On the summit of Mount Diablo stood the Coyote, Hummingbird and Eagle (or sometimes a Hawk). The Coyote is a particularly significant symbol; the Coyote taught humanity how to survive.

One of the variations of the myth has the flighted birds going in search of land under the water. In another, the Coyote marries two beautiful woman he is flown to by the Eagle. The first flees but the second bears his children, repopulating the Earth with the Ohlone.

Yet what of its name? Why is this mountain, sacred to those who have inhabited the lands for thousands of years, now named after the devil?

It certainly wasn’t the mountain’s first name. Before its current devil-ish name, the mountain had been known as:

• Tuyshtak – ‘at the dawn of time’ (Ohlone peoples).
• Sukkú Jaman – ‘the place where dogs came from’ (Nisenan peoples).
• Cerro Alto de los Bolbones – ‘High Point of the Volvon’ (Spanish, the Volvon was the Spanish word for the local people).
• Contra Costa – (the name given to the mountain in 1850).

The name Mount Diablo is believed to have first been applied by Spanish soldiers in 1805. Several Native Americans in their custody escaped, or rather vanished into thin air. The Spanish called the peak Monte del Diablo, meaning ‘thicket of the devil’ (monte was later mistranslated as mountain).

It first appeared on an area map in 1824 and was used in other official documents in 1827, but wasn’t officially designated by the United Stages Geological Survey until 1981.

Whether or not the mountain deserves such a provocative name is a matter of conjecture. But with its red sunset glow, sightings of ghostly figures half-a-mile tall and other modern myths who can say whether there are elements of truth in this mountain’s supposed mystical qualities.

GEOGRAPHY OF MOUNT DIABLO.

Mount Diablo is an isolated peak in the northern Californian landscape, 40 km (25 miles) east-north-east of San Francisco. Visible from the Bay, it is a sprawling expanse of rock that heralds the beginning of the Diablo Range to the south-east.

Mount Diablo is known as a ‘double pyramid’ peak. This means it appears to have two distinct peaks, separated by a notable distance. In fact, North Peak (1,084 m/ 3,557 ft), which is the ‘second pyramid’ located around 1.5 km (1 mile) to the north-east, is a subsidiary of the main summit.

It's complex structure includes at least eight subsidiary peaks, including Ransom Point (1,062 m/ 3,485 ft), Mount Olympia (898 m/ 2,946 ft) and Eagle Peak (722 m/ 2,369 ft). These are spread over a very large area and are separated by long ridgelines. Dorner Creek to the north is the destination for many of the mountain streams.

Formation of Mount Diablo.

This mountain complex was formed relatively recently, with much of the uplift occurring within the last two million years.

The rocks found lower on the slopes and on the outer peaks are younger than those found higher up and centrally. The older rock, up to 165 million years old, was formed as part of an ancient ocean crust. Newer sedimentary deposits overlay this harder bedrock, compressing to form softer sandstone and shale.

While the harder bedrock pushed through the softer rock during the recent uplift, the softer rock remained like a coating over all but the highest points. Time has work this coating away, leaving fascinating structures such as wind caves and tunnels dotted across the mountain.

Mount Diablo Wilderness.

Mount Diablo’s protected area, known as the Mount Diablo State Park, has grown from 6,000 acres in 1971 to over 110,000 acres today.

This is down in large part to the efforts of voluntary organisation Save Mount Diablo. Fifty percent of the mountain still rests under private ownership (to the west) and this charity’s goal is to buy that land for public ownership. This preserves the mountain for hikers, bird watchers and mountain bikers alike, saving it from building development.

Drive to the Summit.

The summit of the peak has been reachable by vehicle since 1874, when the 24 km (15-mile) Mount Diablo Summit Road was opened. Today it is accessed via the North Gate or South Gate Roads, both of which enter the State Park on the western side and join at the Mountain House site.

The building of a summit road reflects both the summit’s modest elevation and shallow-sloped terrain, but also its significance in local surveys since early settlement. Mount Diablo, so easily recognisable from great distances, was the main reference point for much of the survey work first completed.

WILDLIFE OF MOUNT DIABLO.

Flora.

A third of California’s plants are endemic to the state. Of Mount Diablo’s 900 species of vascular plants, 75% are found only in California. What’s more, 11 are endemic to Mount Diablo, while 29 are only very rarely found elsewhere.

Two endemic species were found recently, (the lime ridge navarretia and the wooly star) while another was rediscovered after a presumed extinction (Mount Diablo Buckwheat).

Endemic plants of note include the yellow, downward-facing bulb flowers of the Mount Diablo globe lily and the delicate lilac flowers, with distinctive white borders, of the Mount Diablo jewel flower. There is also a native thistle (Jepson’s coyote thistle) found only on the mountain’s slopes.

A view of the mountain’s slopes from the summit reveals a mosaic of different colours and tones of green. The slopes are variously populated with open stands of pine forest, gold firn, chaparral, oak woodlands and open grassland. With a low elevation, trees grow up to the summit.

Fauna.

When settlers first arrived in this area, part of the attraction was the large population of grizzly bears, which were popular to hunt. As a result, grizzly bears, wolves, tule elk, pronghorn antelope and the grey squirrel are now extinct in this area.

The many animals that remain are part of precise and fragile ecosystems. For example, the pine trees support an ecosystem of woodpeckers, tarantulas, western rattlesnakes, Alameda whipsnakes, tarantula hawks and eagles. Gold firns support California ground squirrels and California whiptails among others.

Of the larger creatures, mountain lions are the rarest, while bobcats, grey fox and coyotes are only occasionally seen. More regularly social mammals include raccoons, long-tailed weasels, opossums and black-tailed deer.

You may wish to bear in mind that Tarantulas are most frequently visible in September and October, as this is their primary mating season. Many other smaller creatures, like desert cottontail rabbits, are often best seen crossing the warm summit roads during summer.

This peak also hosts an abundant insect life, including four butterflies found only in this area. All swallowtails, these butterflies are part of 22 species that flutter across the mountain along with four species of dazzling dragonflies.

FIRST ASCENT OF MOUNT DIABLO.

As with many peaks of lower heights and shallow slopes, ascertaining the first ascent is very difficult. It may well be that, as the white settlers arrived in great numbers from 1848 onwards, the peak was not seen as much of a challenge to conquer so the first ascent was never particularly noted.

It had certainly been climbed by 1861. This was when Whitney’s California Geological Survey visited the peak, took samples and established the mountain’s height. However, it is highly unlikely that this would have been the first ascent, and we can assume it also pre-dated 1848, as there had been a Spanish presence in the area since the turn of the century.

CLIMBING GUIDE FOR MOUNT DIABLO.

With trails criss-crossing the mountain, and numerous summits to aim for, climbing Mount Diablo is far from a singular adventure. Some routes will be shared with mountain bikers, trail runners and horse riders, with a number of wide dirt roads also doubling up as hiking trails.

There are five main trailheads on the mountain, scattered around the north and south sides. These include: the approaches from the North and South Entrances; the Mitchell Canyon trailhead (popular with mountain bikers); the Regency Road trailhead (near Donner Canyon); and the Marsh Creek Road trailhead (for the Mount Olympia Trail).

Juniper Trail.

Except for driving to the summit, the Juniper Trail is the easiest summit ascent on Mount Diablo. A 4 km (2.4-mile) return, it can be completed in a couple of hours. This is a great option if you have a diverse group or are wary of straying too far from the comforts of modern living.

Well-marked though not always well maintained, it begins at the Laurel Nook Group Picnic Area, climbing through woodland to the Moses Rock Ridge Trail. Head along the ridge to the right, then cross the Summit Road to locate the Summit Trail.

The next section passes satellite antenna to arrive at the lower car park. Follow the trail between the road as it forks (the trail is right up the middle). Another “antenna farm” is traversed before arriving at the summit, whose blue-roofed visitor centre and museum makes it obvious that you’ve arrived!

Four Summits.

A popular early season training hike, this long hike bags four summits: Mount Diablo, North Peak, Mount Olympia and Eagle Peak. A rough estimate of length is 22.5 km (14 miles), as the network of trails and fire roads make it possible to cut your own preferred route. With this in mind, make sure you acquire a map in advance.

Starting from the Mitchell Canyon Trailhead (195 m/ 640 ft), follow the Mitchell Rock trail south. Passing Twin Peaks, turn right at the junction with the Eagle Peak Trail and head straight up your first summit of the day.

Drop down then climb up to Murchison Gap (707 m/ 2,320 ft), following the Bald Ridge Trail to gain Prospectors Gap (1,207 m/ 2960 ft) before heading towards the main summit on the North Peak Trail. If desired, a good variation is an unmarked but well-worn trail through the rocks to your right. This offers a class-II scramble up the Devil’s Pulpit, and cuts a decent amount of time from the hike.

From the main summit, head back to Prospectors Gap, then follow the North Peak Road to North Peak. From here, take the ridgeline (harder) or follow the North Peak Trail to Mount Olympia, before picking your route back to the trailhead (there are many options, each with their own pros and cons).

Mount Olympia Trail

This hiking trail begins to the north-east of the main summit, and bags three separate peaks en route. The Mount Olympia Trail tends to be a very quiet route, which is perhaps another benefit of it.

To bag all three peaks and return is a long day’s hiking up steep slopes 19.5 km (12 miles return), so is a worthy challenge anyone wishing for a devil-ish test!

The hike begins at the Marsh Creek Road trailhead and follows the steep Mount Olympia Trail (ignore Mt Olympia Road signs) up the hillside to the modest Mount Olympia. A descent to the ridgeline soon begins to climb again, leading you to a short detour through Juniper and Bay forest to reach North Peak.

To reach the main summit, it’s better to descend the opposite (north-east) side, as the direct descent towards the main summit via the fire road is treacherously steep. Descend to Prospector’s Gap then onto the main summit (another 3 km/ 2miles).

Other summit hikes are:

• Back Canyon – a direct 19.5 km (12-mile) return from the north with significant elevation gain, though there are variants that can help to reduce this a little.
• Moses Rock Ridge – climbs the grassy west ridge of Mount Diablo, sharply contrasting the rocky ascents found elsewhere.
• Summit Trail – a half-day hike from the south through woodland, offering a range of options for the summit approach.

INFORMATION ON TREKKING AROUND MOUNT DIABLO.

The Mount Diablo area contains 40 parks and around 840 km (520 miles) of defined hiking trails. These have been compiled by Save Mount Diablo into a comprehensive guide.

To take a less direct route to the summit, the Grand Loop Trail is a 11.25 km (7-mile) takes you around the northern area of the peak before reaching the summit.

Beginning at Juniper Campground, you first head up wide roads to Deer Flat (646 m/ 2,120 ft). Head across undulating terrain on Meridian Ridge Road, Prospectors Gap Road and on to Big Springs (632 m/ 2,073 ft).

Prospectors Gap is a junction for many trails, so be careful to take single-track North Peak Trail heading towards Mount Diablo’s main summit. A steep, wooded trail leads you to the summit. The descent completes the loop, with Juniper Campground only 2 km (1.25 miles) downhill to the north-west.

Mount Diablo North Peak Trail is a 10 km (6-mile) difficult return that climbs 673 m (2,208 ft). This route begins near Walnut Creek and can be started from a number of trailheads as the actual trail is not well marked. For the most part, the trail is shaded by woodland, something that you’ll be glad of as you head up the steep path (this is best taken as an autumn hike).

There is also some excellent rock climbing to be enjoyed on the mountain. It is centred around Boy Scouts Rocks, where there are at least 23 different routes offering a range of difficulties.