Mt. Diablo Summit Loop – PacificStateHiking

Date Hiked: 12/2015, 10/2021
Rating: 8
Distance: Varies depending on route, roughly 10 miles round trip
Difficulty: Strenuous
Best Season: Anytime, though summer might be too hot; Spring would be my choice

Looking up toward the Mt. Diablo summit from the trail on the south side

Mt. Diablo is one of the most prominent landmarks in Northern California, looming large over the Bay Area and Central Valley. It’s famous for the prominence of its summit, and is often cited as having the widest angle of view in the western hemisphere. Whether or not that’s true, it’s an incredible view in every direction, at least when the skies are clear enough. While you can drive right to the summit, it’s a lot more satisfying to hike to the top on foot, if a lot more effort, and while you’re at it you can make a grand loop around the mountain, hitting a couple side peaks along the way if you so desire.

Looking north toward the Carquinez Strait.

The rolling oak and grass covered hills typical of Diablo.

While you can start this loop hike from a few places from the base to the summit itself, a clockwise route from Juniper Campground is ideal because you have the summit to look forward to and a nice downhill to finish the hike. Though the route is pretty obvious I recommend carrying a park map for junctions and to give you a better idea about optional side trips. As far as those go the two main options are Eagle Peak and North Peak, and I recommend both if you have the energy. Going clockwise each one is higher than the last, finishing up with the Mt. Diablo summit itself.

Mt. Diablo summit from the Eagle Peak trail

While the circuit isn’t that difficult, there is a lot of up and down. And the side trips are definitely more difficult. The route to Eagle Peak traverses a ridge on a narrow trail. And the trail to North Peak has the steepest stretch of trail on the entire circuit. It’s on a beat up fire road, partially paved, and that eroded surface made the footing pretty difficult. So unless that’s been fixed in the years since I’ve done it, there’s your fair warning.

Looking toward the Sacramento River Delta

The southeast portion of trail after you pass the turnoff to North Peak might just be my favorite stretch of trail. It’s very pretty with some fine rock formations, and you can see the summit building much of the way. Once you make your way to the summit you’ll find yourself in a much more crowded scene, but at least you’ll feel like you earned the views. From there you just head west back down toward Juniper Campground.