Mount Diablo North Peak

View into Livermore Valley

4 miles round trip, 1200 feet elevation gain
Difficulty: Easy-moderate

Access: Paved but windy road to trailhead, Mount Diablo State Park entrance fee required

North Peak is the oft-overlooked shorter sibling to the well-loved and ever-popular main summit of California's Mount Diablo, the iconic double-peaked mountain visible from much of the San Francisco Bay Area. Real estate agents in nearby Walnut Creek once promoted a false claim that Mount Diablo had the largest viewshed of any point on Earth after Kilimanjaro, but the fact that those claims were even somewhat believable gives you an idea of the sweeping panorama from the mountain. While a road leads to an observation tower crowning the main peak of Mount Diablo, 3557-foot tall North Peak is accessible only by hiking and is thus far quieter; although the summit experience at North Peak can be somewhat marred by the extensive collection of telecommunications equipment at the summit, the lovely panoramic views still make this an enjoyable hike. This hike is best in winter and spring, when there is less air pollution and the grassy slopes of Diablo are green.

I hiked North Peak on a clear February weekday, when the weekend crowds that descend on Mount Diablo State Park were absent. The trailhead can be accessed by either the North Gate or South Gate Roads into Mount Diablo State Park, which come from Walnut Creek and Danville, respectively. I arrived from Danville: I left I-680 at exit 39 and followed Diablo Road to the northeast, making a right turn after 0.7 miles to stay on Diablo Road. I followed Diablo Road for another 2 miles and then turned left at the junction for the Mount Diablo State Park Road; signs just before the junction indicated a turn for Mount Diablo State Park and the Athenian School. I followed this narrow paved road through a tony neighborhood before the increasingly windy road entered Mount Diablo State Park; I passed the entrance kiosk and then after 7 miles of driving from the turn on Diablo Road I came to a junction with North Gate and Summit Roads.

Turning right at the junction onto Summit Road, I followed Summit Road uphill for another 3.5 miles to a sharp, eastern-facing switchback just below the summit, where there were wide gravel pullouts on either side of the road. This unsigned parking area is the start of the hike to North Peak. New expanded bike lanes have eaten into some of the parking, but there's still room for ten cars or so to park. If you struggle to park here, you can continue uphill on Summit Road, park in the large lot near the summit of Mount Diablo, and follow the Summit Trail back to the this trailhead.

Leaving from the eastern edge of the switchback on Summit Road, the North Peak Trail led east across the open and grassy south slopes of Mount Diablo. On the very clear day of my hike, the views were absolutely expansive here: closer by, the rolling green grassy hills of Morgan Territory lay below, with the suburbs and shopping malls of the Tri-Valley beyond that and the Diablo Range peaks at Sunol and Ohlone Wildernesses rising beyond Livermore and Pleasanton. To the east, I could see clear across the Central Valley to the snowy peaks of the Sierra Nevada!

North Peak Trail wrapping around Mount Diablo

I followed the North Peak Trail gradually downhill as it wrapped around the south side of Mount Diablo's main peak. At one-third of a mile, the trail came to the southeast ridge of the mountain, a rocky spine leading towards the summit that featured the Devil's Pulpit, an enormous outcrop. Beyond the Devil's Pulpit, I could see all the way to the stone observation tower built atop Mount Diablo.

Devil's Pulpit and the observation tower atop the main summit of Diablo

The southeast ridge also offered sweeping views to the south and west, including some of the best views of San Francisco Bay on this hike. Much of the bay itself was visible, its waters glimmering in the sunlight. The Santa Cruz Mountains rose behind the Bay, with peaks such as Montara Mountain, Black Mountain, and Mount Umunhum clearly distinguishable.

View towards San Francisco Bay and the Santa Cruz Mountains

As the trail turned the corner around the southwest ridge, I found a great view of North Peak. From here, the trail ahead was clear: I could see the North Peak Fire Road that I would later follow running up the ridge of North Peak until eventually reaching the cluster of communications towers at the summit. Beyond North Peak, the watery veins of the Sacramento-San Joaquin Delta snaked across the Central Valley and even further back were snowy Sierra Nevada peaks.

North Peak across Prospectors Gap

After coming around the southwest ridge, the trail descended via a pair of short switchbacks and then entered a forest. Over the next two-thirds of a mile, the trail descended constantly, with more limited views; the final stretch of descent down to Prospectors Gap was quite steep.

One mile from the trailhead and after about 500 feet of descent, the North Peak Trail arrived at Prospectors Gap, a saddle between the main summit and North Peak. Here, the trail crossed Prospectors Gap Fire Road, which led downhill on either side of the ridge; across the road, I connected onto the North Peak Fire Road, which led uphill along a ridge towards the summit.

The North Peak Fire Road was very aggressive in its initial ascent up from Prospectors Gap, with some sections that were quite steep. The first half mile of ascent along the fire road generally stuck to the southern side of the ridge and provided more views out west and south to the main summit and the Tri-Valley. At 1.5 miles, the trail crossed over to the forested north side of the ridge, where the trail flattened out and provided some temporary respite; however, at 1.7 miles, the trail became extremely steep as it tackled the final push to the summit of North Peak. This stretch of the fire road was actually quite tricky to negotiate: gravel covering the fire road made the trail surface loose and slippery and the angle of the ascent was high enough that I was struggling to get traction with my boots. When this short hundred-meter stretch ended, I found myself arriving at the broad-sloped summit area, reaching the base of the telecommunications towers atop the peak at just over 1.8 miles.

The presence of so many towers on the summit certainly detracted from the scenery to a degree; the summit itself was best for views west towards Mount Diablo's main summit and towards the Tri-Valley. Pleasanton Ridge and Mission Peak rose at the far end of the Tri-Valley area, with Loma Prieta's distant but high peak visible behind them. 

Looking back to the main summit of Mount Diablo

View of the Tri-Valley, with Mission Peak and Loma Prieta in the distance

The most enjoyable part of the Mount Diablo North Peak view, however, was found from a small knoll to the northeast of the high point. I followed the fire road counterclockwise around the communications towers and found a social path leading towards a low prominent point along the north ridge. The path died out upon reaching a rockier section of this ridge; there were plenty of rocks here where hikers can relax and enjoy the views to the north and the east.

What lovely views! The Central Valley lay below me, the Sacramento-San Joaquin Delta clearly visible beyond the suburbs of Antioch. The Shiloh Wind Farm- a 500 MW project- was spread out across the delta, which is a wetland of extraordinary ecological diversity. Beyond the Central Valley rose the snowy Sierra. I could clearly make out Pyramid Peak near Lake Tahoe and could see a less distinguishable snowy mass stretching south towards Yosemite National Park. The isolated hills of the Sutter Buttes were visible in the middle of the valley to the north, with the snow-capped and rounded form of Lassen Peak, the southernmost of the Cascade volcanoes, just barely visible.

Suisun Bay lay beyond the nearby suburbs of Concord; a patch of oil refineries dotted the shoreline near the Carquinez Strait. The open pit of the Clayton Quarry is clearly visible, a mountain being deconstructed to make concrete in our cities. Mount St. Helena, Cobb Mountain, and even distant Snow Mountain rose to the north in the Coast Ranges. San Pablo Bay was visible in the distance, with Mount Tam's distinctive profile clearly visible. At the very edge of the view, I could see past the Oakland hills to the Golden Gate Bridge, the San Francisco skyline, and a flotilla of cargo ships waiting to be unloaded at the Bay's many ports.

View towards the Suisun and San Pablo Bays

The Central Valley and the Sacramento-San Joaquin Delta

San Francisco skyline rises behind the Oakland hills

Snowy Sierra Nevada rises over Sacramento-San Joaquin Delta

The view was sweeping enough that for a moment I could imagine that it could be the second largest viewshed in the world, as pamphlets in the mid-20th century claimed. This, of course, was hogwash invented to sell houses in Walnut Creek- Mount Diablo's viewshed is ultimately not even the second largest in California. Still, this was a grand panorama and I was glad to enjoy it all by myself on my hike. Weekends bring far more visitors to this park, so come early or come on a weekday to enjoy the views from Diablo's sibling peak.