Rock City, near Mt Diablo, California, is one of the West Coast’s great natural curiosities.
Wait, you might be thinking, isn’t Rock City near the Smoky Mountains? Nope, those “See Rock City” signs that you see along the highways of the Appalachians point to another attraction. The places we want to tell you about are 2,400 miles away.
What’s there to do at this Rock City, the one that’s just a stone’s throw from Mount Diablo?
Let’s find out!
Where Is Mt Diablo State Park?
Mount Diablo State Park is an isolated 3,849-ft peak in Contra Costa County in northern California. It’s about 40 miles east of San Francisco and just 32 miles from Oakland via State Highway 24. It’s about 70 miles west of Stockton and 85 miles from Sacramento.
Mount Diablo is a tremendously popular destination for motorists and cyclists because you can drive (or pedal) right to the top. From a distance, depending on the angle, it looks somewhat like two pyramids side by side.
Things to Do at Mount Diablo State Park
Standing tall above the San Ramon Valley, the mountain offers a commanding view of the entire East Bay area. You can spot the Golden Gate Bridge on a clear day, and you may even see for 200 miles.
It’s a popular overlook area, but you’ll have other activities on and around Mt. Diablo, including Rock City.
Hike to the Summit of Mount Diablo
You can drive or bike to the summit or take a hike. It’s no easy walk in the park, though. Expect a challenging uphill climb that gains almost 3,000 ft over 3.5 miles.
The return trip down is a cinch, though, and the views are incredible. The terrain is rocky, and the trail is narrow in places. It has benches so you can take a quick break if you want.
Go Camping
If you want to stay overnight, Mount Diablo has three campgrounds for tents and smaller RVs. Choose wisely as some are big, level, and spacious while others are small and slightly slanted.
Most sites have shade with mature trees, and all have a table, fire ring, and grill. All three campgrounds have drinking water and flush toilets, and one of them has showers.
Walk Around the Summit Visitor Center
The visitor center is a historical place built in the 1930s from sandstone quarried from the park. Inside, you’ll get to view exhibits that detail the cultural and natural history. Visiting here will give you a better appreciation for the flora and fauna you may encounter during your next activity.

Hit the Biking Trails
You’ve probably seen some cyclists on the streets leading to the park, but it’s also a great place for off-roading. MTB Project recommends four routes for mountain biking, rated intermediate or difficult.
One of their top choices is the Creek Loop, which is 6.8 miles down a road with “a fun descent into creek beds that are sometimes filled with water.” This trail is just one of many that cover 116 miles.
Traveler’s Tip: Head towards the San Francisco coast in California and explore these five inspiring lighthouses.
What Is Rock City in Mt Diablo State Park?
Like the one back east, in Lookout Mountain, Georgia, the natural formations of Rock City near Mt Diablo are a big attraction. This California version is like a natural playground of unusually shaped boulders.
Some of them have big openings called wind caves, and the surrounding area has shrub-like Manzanita trees. This unforgettable 20,000-acre state park lies off South Gate Road about a mile north of the South Gate kiosk.
Things to Do at Rock City
This place is truly fun for the whole family. You’ll have trouble resisting climbing up onto these big rocks, which you can easily do on some of them.
You may also enjoy reading the graffiti carved into them over the decades. Here are some terrific ways to pass more time at Rock City at Mt Diablo State Park.
Climb Atop Sentinel Rock
First on our list, is Sentinel Rock, a 1.2-mile hike that starts and ends at a landmark called Elephant Rock. This is one of the most popular things to do at Rock City, and it would take about a half-hour if you rushed right through. Don’t, though.
Take your time and explore the rock formations and caves along the way. Also, take your binoculars; you may see the Half Dome at Yosemite from the top.
Explore the Wind Caves
These dramatic openings in the sandstone were formed over time by erosion, not wind. They may be the most captivating features along the trail that snakes through this gorgeous slot canyon.
Additionally, you may want to pull yourself inside the openings and pose for a picture. Or dive into the details of this fascinating slow-motion sculpting process.

Picnic at Elephant Rock
You can also picnic at Elephant Rock. Yep, it kind of looks like an elephant. It might be one of those visual tricks where you don’t quite see it, and then you do.
This popular rock feature is just off South Gate Road and close to the turnoff for the Live Oak campground. Hopefully, you can grab some seats at one of the picnic tables and enjoy a leisurely lunch or snack.
Walk the Trail Through Time
Next, you can walk the Trail Through Time. This unique outdoor exhibit uses a series of interpretive panels to tell a story that started 180 million years ago. It’s the story of the tectonic plates that rose from the earth to create this weird, wild wonderland.
As you hike up the 6.25-mile incline, the rocks get progressively older. Each stage of the trail is a different chapter regarding climate, landscape, and plant and animal life.
Overnight at Live Oak Campground
Finally, out of Mount Diablo State Park’s three campgrounds, this is the one closest to Rock City. It’s very close to the South Gate entrance. Just turn by Elephant Rock and look for the sign.
The Civilian Conservation Corps built Live Oak Campground in the 1930s, and it retains the rustic charm of that era. Sites have a distinctive stone wood-burning stove, a picnic table, and a fire ring.
Additionally, this is the campground that has showers in addition to drinking water and flush toilets.
Rock City and Mt Diablo Is Worth a Visit
Rock City and Mt Diablo tend to attract people who love the outdoors and unusual landscapes. It’s northern California’s version of the famed Joshua Tree National Park farther south.
From a geological standpoint, these odd sandstone features result from sediments washing down in rivers flowing from the Sierra Nevada Mountains.
But even if you know the scientific explanation, they seem to have an air of mystery about them. Next time you’re in the Bay Area, Rock City and Mt Diablo are definitely worthwhile diversions. They offer magnificent scenery you won’t forget.