At the eastern fringe of the San Francisco Bay Region, Mount Diablo, elevation 3,849 feet, stands alone on the edge of California’s great Central Valley. At this point, the Coast Range consists only of low hills, none high enough to block the view from the upper slopes of the mountain. As a result, the view is spectacular. Many visitors to Mount Diablo head straight for the summit to enjoy the famous view. Summer days are sometimes hazy, and the best viewing is often on the day after a winter storm. Then, you can look to the west, beyond the Golden Gate Bridge, to the Farallon Islands; southeast to the James Lick Observatory on Mount Hamilton at 4,213 feet elevation; south to Mount Loma Prieta in the Santa Cruz Mountains at 3,791 feet elevation; north to Mount Saint Helena in the Coast Range at 4,344 feet, and still farther north to Mount Lassen in the Cascades at 10,466 feet. North and east of Mount Diablo, the San Joaquin and Sacramento Rivers meet to form the twisting waterways of the Delta. To the east beyond California’s great Central Valley, the crest of the Sierra Nevada seems to float in space. With binoculars, you may even be able to pick out Half Dome in Yosemite National Park. Mount Diablo State Park is one of the ecological treasures of the San Francisco Bay Area. Every season in the park has its special qualities. Discover for yourself the mountain's beautiful wildflowers, its extensive trail system, fascinating wildlife and distinctive rock formations. View the stars from its lofty heights, bike ride to its 3,849 foot summit or explore the more remote trails by horseback. The park offers hiking, biking, horseback riding and camping. Dogs must be on a leash under your control at all times. Dogs are not allowed on trails. Dogs must be in a tent, camper or enclosed vehicle during the night. Gates open 8am and close at sunset. Visitors should plan to be in their vehicles by sunset and headed out to avoid being locked in.
Some great things, some bad things.
Pros: Beautiful hike, varying scenery, cool rock formations!
Cons: Seriously lots of freshly broken glass/bottles in a few parts of the trail. Hard to clean up, so sad. But even worse, tons of graffiti and carvings in the rocks. I think we counted three penis carvings of various sizes. Such talent people have. -_-
The trail was a bit confusing at times, but we made the best of it and it was a blast! Since we had previously hiked to the summit we decided to do a little loop and check out Sentinel rock. Overall awesome but sadly rated it down due to people abusing the place.
Had a great time hiking with a friend and my two 10 year old brothers. My brothers struggled a little bit towards the end but all in all it was a great hike that was shaded for over half the time. Beautifully scenery and would definitely do it again!
Great hike. I preferred it a few years ago when areas had recently been burnt out, but it's fantastic nonetheless. I had a hard time finding parking when I went, so I added some detail about where to go on my trip report here, which may help others: https://gregable.com/2014/01/mt-olympia-hike-part-of-mt-diablo-state.html
Definitely not a "hard" trail, though navigating some places would have been challenging without GPS and following the map trail rather than just the red line trail on AllTrails. We hiked from the Juniper Trail toward summit trail at the parking lot, up to the North Peak. About 7.5mi there and back. Some steep sections, nice scenery, amazing sunset views on the hike back.
We did this route clockwise with some variations. We start at the Diablo Valley Overlook (DVO) parking area (near Juniper campground). We hiked to the summit with a short side trip to Moses Rock Ridge, taking the Mary Bowerman Trail around the summit and then up to the summit itself for a break. We then went down to the south, connecting with the Summit Trail and returning to the DVO via the Juniper Trail. This hike was 6.5 miles, 1,371 feet of climb with many great views.
Great hike! It's fun to hit the three different peaks. We hiked on a ridiculously hot day so the water fountains and restrooms right before the accent to Mt. Diablo saved us. I feel like the views from Mt. Olympia are just as good as the ones from Mt. Diablo so if you only have time for the first section then it's still worth it. I think the most interesting part of the hike was through the meadow between Olympia and North Peak, really awesome yellow fields on a narrow path. We ended up using our headlamps for the last hour on the way down, it's really tree covered so if you even think you might be heading down around dusk be sure to have a light!
Great trail however the trailhead and starting point are not clear. Read above comments for best directions.
Plan more time than expected. I accidentally ended up hiking a portion of the trail in the dark. I was prepared with a headlamp however because of the nature of the trailhead not being clear it could be easy to get turned around. Near rock city there is a huge network of social trails, just be aware and take a gps point of where you parked your car.
Incredible views and beautiful around to rock city!! Great diversity of ecosystems and terrain. Awesome summit.