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Mount Diablo State Park

Juniper, North Peak Trails,

“The Grand Loop” is 7 miles round trip with 1,700 foot elevation gain

From the Golden Gate to the Farallon Islands, from the High Sierra to the Central Valley—this is the sweeping panorama you can savor from atop Mount Diablo. Geographers claim that hikers can see more of the earth’s surface from the top of Mount Diablo than from any other peak in the world with only one exception: Africa’s legendary 19,340-foot Mt. Kilimanjaro.

The far-reaching panorama from Mount Diablo is all the more impressive considering the mountain’s relatively short (elevation 3,849 feet) height. Two reasons for the grand views: (1) the mountain rises solo very abruptly from its surroundings, and (2) the land surrounding the mountain—the San Franciso Bay and Central Valley—is nearly flat.

Geologically speaking, the mountain is a bit odd in that the hiker climbs over successively older and older rocks on the way to the summit; this is exactly the opposite of the usual progression. Much of Diablo’s sedimentary rock, which long ago formed an ancient sea bed, has been tilted, turned upside down and pushed up by a plug of hard red Franciscan rock.

Even those hikers without any interest in geology will be impressed by the bizarre, wind-sculpted rock formations bordering a picnic area on the mountain called “Rock City.” The mountain’s rock show also includes the satanic-looking Devil’s Pulpit, located just below the summit.

Several colorful yarns describe how the mountain got its name. The most popular account supposedly arose from an 1806 expedition of Spanish soldiers from San Francisco Presidio who marched into the area to do battle with the local Indians. In the midst of the fighting, a shaman clad in striking plumage appeared on the mountain. The Spaniards were convinced they saw El Diablo—The Devil—and quickly retreated.

In 1851, Mount Diablo’s summit, long a landmark for California explorers, was established as the official base point for California land surveys. Even today, Mount Diablo’s base line and meridian lines are used in legal descriptions of much California real estate.

Toll roads up the mountain were opened in the 1870s and a fancy hotel was built. In order to make their California holiday complete, tourists of the time just had to climb Mount Diablo and take in the majestic view.

In 1931, the upper slopes of Mount Diablo were preserved as a state park. In more recent years, the lower slopes were added to the park, thanks in a large measure to the efforts of Save Mount Diablo, a local conservation organization.

Today the park consists of some 19,000 acres of oak woodland, grassland and chaparral. Stands of knobcone and Coulter pine, as well as scattered digger pine, are found all over the mountain.

Mount Diablo boasts some fine trails but the state park is primarily oriented to the automobile. Something of the majesty of conquering Diablo is lost for hikers when they’re joined at the top by dozens of visitors stepping from their cars.

Still, there are plenty of places on Diablo’s flanks where cars can’t go. And the road to the summit, while intrusive, does allow hikers to easily customize the length of their day hike.

Want an easy hike? Start walking just below the summit. Want a vigorous aerobic workout? Start hiking at the base of the mountain and trek all the way to the top.

A relatively easy way to the top is via two mile round trip Juniper Trail. More ambitious hikers will tackle the 6 mile round trip Summit Trail.

A great way to tour the park is to follow what park rangers call “The Grand Loop,” a seven mile circuit that connects several trails and fire roads and offers views of—and from—Diablo in every direction.

Directions to trailhead: From Highway 680 in Danville, exit on Diablo Road and go east. After three miles, go north on Mount Diablo Scenic Boulevard, which becomes South Gate Road, then Summit Road, and winds 8.5 miles to Laurel Nook Picnic Area. Park in the wide turnout (Diablo Valley Overlook), then join signed Juniper Trail, which departs from the picnic area.

The hike: From the picnic area, the path ascends northeast over brushy slopes. After crossing paved Summit Road, the path climbs some more up to the lower summit parking lot.

Plan to spend some time on the summit enjoying the view. A couple handy locator maps help identify cities and natural features near and far.

After you’ve enjoyed the view, join the trail heading east from the south side of the parking lot. The path parallels the road for a short distance, then reaches a junction. Summit Trail heads southwest down the mountain, but you join the eastward-trending trail to North Peak.

Enjoy the awesome view of the Central Valley as you march over a rocky, juniper-dotted slope. The red-brown rock formation above looks more than a little diabolical; the most prominent rock formation is known as Devil’s Pulpit. A half mile from the above-mentioned intersection, the trail, sometimes called Devil’s Elbow Trail, sometimes called North Peak Trail, angles north and descends to a distinct saddle, Prospectors Gap. At the gap is a junction with the rugged 0.75 mile long dirt road leading to North Peak.

Our path contours along the bald north slope of Diablo, passing junctions with Meridian Ridge Fire Road and Eagle Peak Trail, and arriving at Deer Flat, a pleasant rest stop shaded by blue oak.

Intersecting Deer Flat Trail, you’ll switchback up to Juniper Campground, then continue a short distance farther to Laurel Nook Picnic Area, where you began your hike.

© 2012 The Trailmaster, Inc.
From John McKinney’s
Day Hiker’s Guide to California’s State Parks
Trail descriptions and maps have been reproduced with the permission of the author.  To learn more about The Trailmaster and other related publications please visit their website at