Mount Diablo State Park

When we visited the Black Diamond Mines regional reserve the ranger told us a bit about Mount Diablo. Mount Diablo is a pretty young mountain and when it rose all the geological features of the area changed. In the Black Diamond Mines you can observe that the different geological layers are tilted and they all rise towards Mount Diablo. The ranger got us interested and we wanted to explore the area for ourselves. So we headed off to Mount Diablo State Park for a strenuous hike. According to the hike reviews on the web the most interesting hike is the so called "grand loop" that starts halfway up to the top of Mount Diablo and goes complete around it, covering three different peaks on the way.

The official "map" for this state park is really bad, many trails are not on the map and the scale is too coarse grained plus the trail heads are not marked well. My advise is to bring a GPS (e.g., a Garmin) with the OpenStreetMap maps of California. These maps include all trails of the state park and will help you during your hike.

Health warning: you are exposed to direct sun light through most of the hike plus it is super hot, even in September. Bring plenty of water (at least 3/4 of a gallon - 3l per person).

Trail navigation

The trail head is located right next to Juniper campground, there is plenty of parking (10$) available at the nearby campground. This hike is a grand loop around Mount Diablo with three peaks that you can climb. Depending on your condition you can do one, two, or all three peaks. Follow Deer Flat road to Meridian Ridge road. The first peak you can climb is Eagle peak (follow Eagle Peak trail), which offers a nice view of the area and some old open mining regions. When returning from Eagle Peak trail take the Bald Ridge trail to get to the trail head to the second peak. North peak is reached by North Peak road by a steep incline of around 0.8mi (1.2km) and the view is so so. The peak is mostly covered by mobile and satellite antennas which tend to spoil the atmosphere. Back track to the end of Bald Ridge trail and continue on the North Peak trail until you reach Summit trail. Summit trail takes you up to the final peak: Mount Diablo. The last peak offers the best views: you can see for up to 200 miles into the different California region and you'll even see downtown San Francisco. Back track using Summit trail and follow Juniper trail to the parking lot. Watch out, the trail head of Juniper trail is hard to find. View Map

Hike description

The length of the hike is only around 10 miles (~16.3km) with ~3680ft (1120m) elevation gain. The hike is very strenuous as you are exposed to the sun during most of the time and Mount Diablo tries to step up to his name. The amazing part of this hike is walking along the ridge to Eagle peak, the steep incline up to North peak, and the magnificent views from Mount Diablo.

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The height profile shows the decline from the parking lot and the inclines to

Eagle peak (2nd peak in the picture), North peak (3rd peak), and Mount Diablo (4th peak).

Picture time

Some pictures that we took on the way up.

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On the Deer Flat road, behind us is the Juniper campground

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After locating a GeoCache.

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Exhausted on Eagle peak.

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View from Eagle peak.

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On the way to Mount Diablo.

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View from the top.

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View towards South.

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View towards North peak.

Summary

Overall I would classify this hike as strenuous 6 hour day hike. The three different peaks are great highlights of this trip. If you get tired on the way you can easily leave out some of the peaks (start off with North peak as this peak is only special because of the steep incline at the end). Watch out to bring plenty of water on the hike, otherwise you'll dry out in the heat!

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