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Mount Diablo State Park, California, United States

Mount Diablo's Grand Loop

A 40-minute audio guide to a panoramic trail encircling one of the Bay Area's highest peaks.

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 (56 votes, 16 reviews)
Difficulty: Moderate
Length: 6.2 miles / 10.0 km
Duration: Half day
Overview: The Grand Loop offers a bird's-eye view of the Bay Area, and sometimes glimpses far beyond, of the Farallon Islands, Mount Lassen, the Sierra Nevada, and the Santa Cruz Mountains. It's also a a hotspot for wildflowers in the spring.

At each of 12 stops in this audio guide, naturalists point out the sights and sounds, tell tales of the mountain's past, and suggest what to look for around the next bend. Photographs help identify plants and animals.

Sponsored by Save Mount Diablo and the California State Park Foundation, this moderately strenuous tour features interviews with Seth Adams of Save Mount Diablo, Ken Lavin of Greenbelt Alliance and Mount Diablo Interpretive Association, and Mike Moran and Beverly Ortiz of the East Bay Regional Park District. Music is by Phil Heywood. Narration and audio production by Joan Hamilton.

The Grand Loop is part of the Audible Mount Diablo series, which combines lively interviews and music with the rush of wind and the chirps, howls, and growls of wildlife. The mission of the series is simple: to help people see and hear (and care) more when they take a walk in nature.

Tips: You can rush through this walk in 2 or 3 hours. For maximum enjoyment, though, allow 4 to 5 hours, and plan for a glorious top-of-the-world picnic. Take plenty of water, especially on hot days in the summer. Spring temperatures and flowers are delightful. Views are generally best the morning after a winter storm. Bring layers of clothing in any season. In the winter you can even encounter snow and ice! Poison oak is a problem on some parts of the trail, but you can easily wriggle around it.

Points of Interest


Getting Started

Where will this adventure take you? Who's coming along? How long will it take? Get the answers in this introductory audio segment.
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Juniper Camp

At this stop, you'll learn the survival secrets of two of the mountain's signature trees--junipers and gray pines--and discover why the fragrant bay laurel is a friend to backpackers.

The next part of the trail is all about views and wildflowers, especially in the spring.
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Juniper Camp

Burma Road

Where Burma Road joins the trail down to Deer Flat, you can almost see forever. It's also a great place to learn about the mountain's leafy north side.
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Burma Road

Deer Flat

With its valley oaks and gray pines, Deer Flat is an oasis for birds.
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Deer Flat

Murchio Gap

That last hill was steep, no? Catch your breath here and learn about the Murchio family, the flashy flower possibilities, and the "promiscuous" manzanita.
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Murchio Gap

On the Knoll

When you reach a high point on Bald Ridge, check out the views to the north. Then learn about Leander Ransom and his ill-fated attempt to plant a flagpole on top of the mountain in 1851.

When you get moving again, keep an eye out for wildflowers. In spring and early summer, some interesting ones lie ahead!
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On the Knoll

Prospectors Gap

Now you're almost two-thirds of the way around the loop. Take a breather and learn about the mountain's mining history.

When you're finished, head out on the North Peak Trail (not the fire road). Look for a signpost that says "to summit trail, 1.02." It's the left fork of the two trails that head south.
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Prospectors Gap

Along North Peak Trail

As you look east toward the Sierra Nevada, listen to what 19th-century explorer William Brewer saw as he gazed out over the same landscape.

Remarkably, in a metropolitan area with some 7 million people, the land to the east and south of Diablo is still vast and open. Save Mount Diablo's Seth Adams talks about successfully reintroducing peregrine falcons here in the 1980s, and how he hopes California condors may find their way here soon.

Stop again when the trail makes a 90-degree turn to the West. If you look up the hill from there, you'll see the summit museum in the distance and, a little closer, a redrock promontory called Devil's Pulpit.
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Along North Peak Trail

Devil's Pulpit

If you have sharp eyes, you may be able to see the antique light on top of the summit museum, which is called "the eye of Diablo." Once a beacon for aviators, today the light is part of a Pearl Harbor commemoration each December 7.
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Devil's Pulpit

Devil's Elbow

Where the trail hits the road, there's an interpretive sign on your left and an elderberry bush on your right that is sharing its space with some poison oak. Look respectfully--and listen as naturalist Beverly Ortiz explains the elderberry's importance to native peoples.
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Devil's Elbow

Lower Summit Parking Lot

Sorry about the paved-over look of this place! It's designed to provide access to nature for people who perhaps are not as intrepid or fit as you are. "It's a sacrifice area," admits Save Mount Diablo's Seth Adams. "It's our opportunity to introduce people to areas we really love--teach them how to use them without damaging them."

While you're here, you may want to take advantage of the restrooms and water fountain straight ahead. Civilization does have its benefits!

You can take a side trip east to the summit from here. But our route proceeds west across the parking lot to a signpost marking the trail back to Juniper Camp.

In the springtime when the ceanothus is blooming the whole hillside below can smell like honey!
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Lower Summit

Know Your Place

On the home stretch, Seth Adams shows us "the Taj Mahal of trees" and explains why he likes to return to this mountain again and again.

It's just a short hike to Juniper Campground from here. Congratulations on completing a challenging circumambulation of Mount Diablo. Hope you enjoyed it!
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Know Your Place
Pictures in this guide taken by: joan_hamilton, copyright 2010 Vader, Joe Oliver, copyright 2010 Horwitz, copyright 2010 Scott Hein, copyright 2010 Joe Oliver, Chuck Szmurlo, Creative Commons, Dave Herr/USFS, copyright 2010 John Karachewski, Wikipedia Commons, Copyright Mike Dillon
We visited for the first time in March of 2014 and again on February 2015. It was beautiful both times, the flowers more better in March though. We also did this guide in reverse, going to the lighthouse first then climbing down. It is tougher on your knees, but the views seemed much better this way. The trail posts could be better, so keep your eyes open to not turn on the wrong trail. If you do go the wrong way try to enjoy it XD.
Visited on Feb 16, 2015

by Gabrielmeh on Oct 20, 2015
The drive alone going up to the trail was terrifying. No rails at all on those winding cliffs so be thankful there are no alcohol and drugs permitted.

My first time hiking in a mountain and they say this hike is moderate. But this Grand Loop hike is a strenuous one due to the steep elevation changes and loose gravel on the terrain. If you have bad knees or ankles then avoid this hike.

What are the dangers you ask? Well some of the sections on this mountain trail have some steep and scary cliffs where you would rather not have a slip and fall. I was concerned for the 4 teenagers I had with me and we got through it.

Your acrophobia (fear of heights) will be tested on this hike. We actually saw a group of hikers turn back the other way because of a particularly steep section with a narrow trail. Bring a camera because the views are priceless. The only thing bad we could say about The Grand Loop hike is that our feet and legs were pretty sore the next day but overall this hike will give you an everlasting experience.

Grand loop hike Footage:

Visited on Mar 19, 2014

by AntoniusW on Oct 25, 2014
I found it a strenuous hike because of loose gravel, high elevation and sun. About 1/3 of the hike is under shades. I did not have a hat and got almost sun sick around noon. I suggest to start the hike early morning and bring a lot of water, wear hat and sunglasses. Enjoyt the panoramic view to all the bay area from this trail.
Visited on Aug 30, 2014

by Samakar on Aug 31, 2014
We did this walk on New Year's Day 2014. Our group was five people who are reasonably fit (a college athlete, 4 regular runners, etc.) with limited hiking experience.

We found the terrain slightly challenging but very enjoyable. The route starts out largely downhill on a wide fire road. We took a detour on Eagle Peak Trail (just for fun) once we reached Murchio Gap and took another detour down Meridian Ridge before retracing our steps.

Despite poor air quality in the Bay Area on the day of our hike we were rewarded with spectacular views in all directions and a nice afternoon's worth of exercise.

The hike is definitely worth undertaking but one shouldn't underestimate the need for water and layered clothing as we went from very comfortable warm weather at the start to cold and windy weather near the end after most of our group had worked up a decent sweat.

Visited on Jan 01, 2014

by jpshaugh on Jan 02, 2014
I would rate this hike as difficult due to some very steep sections, but the views are amazing every step of the way and are your reward for taking this hike.

The drive up is a little scary due to all of the cyclists - with few kick-outs, you have to really be sure before passing or being passed by on the long windy road to the top.

The Grand Loop took us a bit under 3 hours. We started before 10AM and were practically alone for the first half of the hike. We passed a couple of mountain bikers along the road to Merchio Gap and by the time we got to Summit trail, the parking lot was full and the top of the mountain was crowded.

Bring LOTS of water. There is little cover and you will want to stay hydrated for the steep sections. A lot of hikers had poles. If I were to do this trail again, I would use them.

Visited on Oct 13, 2013

by GJohnson39 on Oct 15, 2013
Great day hike! It was listed as a moderate hike but I would say it's more difficult. There are many parts that are very steep going down and up. Watch out for mountain bikers who might be skidding down fast and not see you around corners. Each hiker needs to carry their own water, snacks and have good boots on. Sunscreen is a must because much of it is exposed to direct sunlight. Overall it is well worth the time and effort. Amazing how far around northern California you can see.

Visited on Jul 20, 2013

by DNFIN.2013 on Aug 01, 2013
Amazing views!
Tough for a novice like me, but worth it at the end.
Mapmyhike app showed 1,400' cumulative climb and 6,075 calorie burn before batteries gave out just under the summit.

Remember to take lots of water. Our Camelback style backpack water tanks ran out just under the summit.

Enjoy the views and the work out!

Visited on Jul 26, 2013

by wil.hsu on Jul 27, 2013
Very enjoyable hike. Views are incredible, although the sky was a little hazy the day I went. If you can catch a clear the day after a rain storm, it would be stunning.

Most of it was flat to pretty moderate pitch, but there are a few extended sections of some pretty steep pitch. Check the weather, much of the loop is exposed and it will be scorching in the summer.

Visited on May 05, 2013

by dchu101 on May 10, 2013
Amazing Land.. I hope can back again .. :)
Visited on Mar 23, 2005

by mp3us on Mar 24, 2013
Great hike. Very scenic. I would rate it somewhere between moderate to difficult, because some sections are pretty steep.

Some things to note:

1. The first few sections are flat or even on a downward slope, but the rest of the sections more than compensate for it.

2. It is easy to miss the road that connects point #5 (Murchio Gap) to point #7 (Prospector's Gap); we missed it and took a slightly longer route.

3. Pay close attention to the trail at Prospector's Gap. There are three roads from there, but the trail continues along the narrowest of them -- as noted in the guide above, follow the signpost that says "to summit trail, 1.02 miles".

4. From Prospector's Gap on, the trail is narrow. Watch out for folks on mountain bikes!

Visited on Nov 21, 2012

by vijay.narayanan on Nov 23, 2012
Greta Hike, I recommend starting at the Summit, not as the guide says at Camp 23. Great Views, Not too hot.
Visited on Apr 01, 2011

by on May 02, 2011
Drove to several places up on Mt. Diablo, Saw some of the great rock formations with petroglyphs. There are great areas for bicyclists, hikers and wheel chairs to go in this park. At the top of the mountain is a wonderful nature center with the history of the Mountain and local Indian legends. Information of the wildlife and a great little gift shop there as well!!! They have gret areas for photography and general viewing! You can see the Golden Gate Bridge from the top of the mountain and most other areas around the mountain!!!( Weather pemitting of course!) Call ahead for hours, bacuase the center closes alittle early!!! Well worht the trip though!!! There are also areas for fossil hunting aroung the mountain!!! Not on park porperty of course!!! I have been up on the mountain several times and it has been worth it every time!!!
Visited on Sep 25, 2010

by aynrutter on Mar 04, 2011
My favorite loop in the East Bay! This 6 miles are a great workout and you'll get some excellent views along the way.
Visited on Oct 08, 2010

by benoitz on Jan 25, 2011
I went on this loop with the EveryTrail team last October and had a great time. The views of the bay area from the trail were spectacular--I could even see Mt. Tam and the Sutro tower in San Francisco.

There were a number of sections along the trail that were exceptionally steep, which would be difficult for younger kids or anyone with knees that don't always cooperate. Overall I liked the park and the trail, and hope to come back sometime soon.

Visited on Oct 08, 2010

by chris on Jan 25, 2011

by roniclei on Dec 09, 2010
Very nice

by Castellimark on Nov 21, 2010

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About the Author

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Joan Hamilton is an environmental writer, editor, and sound designer with extensive experience in magazines,...

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