Brazen Diablo Trails Challenge
Walnut Creek, CA
- 50K, Half Marathon, 10K, 5K
- Trail (Unpaved)
- Official race website
Discover the beauty of Mount Diablo and support the cause of Save Mount Diablo! For over 50 years, Save Mount Diablo has worked tirelessly to preserve and increase the open space on and around Mount Diablo. In that time, their efforts have taken us from 6,788 acres of open space … MORE
Local Historical Weather (Apr 04):
| 2026 | 2025 | 2024 | 2023 | 2022 | |
| H (°F) | 80 | 72 | 52 | 58 | 71 |
| L (°F) | 47 | 42 | 43 | 37 | 52 |
Find Nearby Lodging (hotel, rental, etc.):
El Diablo Nieve ❄️😈
This is the toughest race of the year for me. This was my 7th year doing the Diablo 50k, and without a doubt, the best weather I've experienced here in … MORE
This is the toughest race of the year for me. This was my 7th year doing the Diablo 50k, and without a doubt, the best weather I’ve experienced here in April. AND we had SNOW on the higher parts of the mountain! This was my 33rd 50k, and 38th ultra marathon. We started at 0630 and the temps were in the mid 30s, but once the sun came out, it was a most beautiful day! Lots of mud on the course, but the dozen or so creek crossings kept our shoes clean and feet refreshed. The 1.5 mile out and back (just prior to Curry Point, 3 miles round trip) was very very muddy and slippery. Would’ve loved to seen how the race leaders made it through here. The course was slightly adjusted this year. The really super steep downhill part of Mothers was shortened, which was awesome! A change near the end added about 700′ total to the previous years (8100′ vs average of about 7400′ previously.) I’ll add the new map to this review. This made the aid station distances a little different than before. They were as follows:
Little Pine: mile 2.9 (no cut-off)
Rock City: 8 (no cut-off)
Curry Point:13 (cut-off = 11:10 am)
Diablo Summit: 16.5 (cut-off = 12:35 pm)
Juniper: 23.1 (cut-off = 2:55 pm)
Burma: 27.3 (cut-off = 4:05 pm)
As you can see there are really generous cut off times. While this race is very difficult (IMO), with an 11-hour cut off, it is achievable for a lot more people. Averaging a 20-minute pace will get you in before the cut off.
I’m already looking forward to next year’s Diablo 50k! As always, major kudos to the Brazen Crew, and all the amazing volunteers who work countless hours to make sure we’re all taken care of! And props to the 50k sweepers!
Random fact: Did you know that on a clear day, you can see parts of 40 of the 58 counties in California! 🙂
Mi Amigo Diablo!
What an amazing race! For me, this is the toughest 50k I've ever done (~7,500' gain). This was my 6th time doing this race, and this year was the best … MORE
What an amazing race! For me, this is the toughest 50k I’ve ever done (~7,500′ gain). This was my 6th time doing this race, and this year was the best one ever!! The weather was absolutely perfect. Sun stayed behind some clouds for almost the entire day, and the temps were perfect!! I’ve done this race in some brutal heat so this was really nice!! We’ve been getting so much rain (and snow on Diablo) lately that the course was pretty muddy in sections, and the lower part had a dozen or so water crossings. There was also some trail damage and fell trees, which led to a slight course change the day before the race. It wasn’t that big of a change, just a couple new out and backs to and from Curry Point. Brazen crew did an awesome job of letting everyone know about the change and the on course volunteers did a great job directing people. There are 6 well stocked aid stations on this course, with everything you might ever want. Hats off to everyone that ran this race, and kudos as always to the crew and volunteers for another amazing event!!
Love this race
This event takes place at Castle Rock State park at Mt Diablo in Walnut Creek. There are four races that take place. There is a 50k that has 8000 Ft … MORE
This event takes place at Castle Rock State park at Mt Diablo in Walnut Creek. There are four races that take place. There is a 50k that has 8000 Ft of elevation, a half marathon with about 2500 ft, a 10k with 1200 ft and a 5k with about 300 ft. I chose the 5k. Previously, I have run the half marathon in 2016 and the 5k twice.
The 5k course is an out and back with an aid station that you see twice. Because of all the rain that we’ve had this season, we did have 12 stream crossings. Most were ankle deep, but there were a couple that went up to my calves and the streams were wide. There was no way to avoid them, so we all ended up with wet feet. This course is slightly technical because of the streams and the slick rocks and a couple of sections of sandstone that is slick and rutty. I do enjoy this course. Castle Rock Park is quite nice the scenery and all the trails.
Brazen Racing produces great races. All finishers get a very nice medal and shirts. There is plenty of food at the finish including an It’s it Ice Cream Sandwich.
In November, Brazen puts on the Summit Stomp which has a 30k in addition to the half, 10k, and 5k.
Devil made me do it
This is the toughest race I do all year. I've done 50 milers that are easier. :) But I tell you, there is nothing like finishing the Diablo 50k. This … MORE
This is the toughest race I do all year. I’ve done 50 milers that are easier. 🙂 But I tell you, there is nothing like finishing the Diablo 50k. This was my fifth year doing it and my fastest ever! Weather was perfect.
This race has a very generous cut off time (11 hours), and the best support group ever. Every time I’ve ran this race I am so impressed with how many people stay until the last 50k finisher comes in, just to cheer them on. I always stay, and to see the look on the faces of some people (who perhaps didn’t have anyone there to cheer for them specifically) is priceless. To see their smile when dozens of people are cheering loudly for them, is one of my favorite parts of this race (and the Brazen community).
So if you want to run up to the summit, then up to North Peak, then all around the park, come out and do what I think is the best 50k around!
Harder than I remember
This was my second time taking on the 50k at Mt Diablo with Save Mt Diablo and Brazen Racing. It was well organized, great aid stations, awesome volunteers and the … MORE
This was my second time taking on the 50k at Mt Diablo with Save Mt Diablo and Brazen Racing. It was well organized, great aid stations, awesome volunteers and the medal is spectacular!
A MUST!!!
Expertly Run. Great AS support. Beautiful scenery. 2500 elevation. 22+ creek crossings. Well marked for the most part. What goes up, MUST come down. Miles 8-10 downhill after 4 miles … MORE
Expertly Run. Great AS support. Beautiful scenery. 2500 elevation. 22+ creek crossings. Well marked for the most part. What goes up, MUST come down. Miles 8-10 downhill after 4 miles up. Should do it once!
THE OLDER I GET- THE FASTER I WAS!!!!!
Most of you already know and appreciate BRAZEN RAZING! You may also know that MT. DIABLO is one of the most beautiful places on earth. A perfect place to race … MORE
Most of you already know and appreciate BRAZEN RAZING!
You may also know that MT. DIABLO is one of the most beautiful places on earth. A perfect place to race when you tire of the usual-it’s unlike any other place at all.
Beautiful course, steep spots
Nice group of people both putting it on and running. Parking down the street was easy- there was a shuttle bus from the high school to the starting area. Don't … MORE
Nice group of people both putting it on and running. Parking down the street was easy- there was a shuttle bus from the high school to the starting area. Don’t be me and not train on enough hills prior to running this. I ran in the area weekly, but choose flatter trails! Oops! There are quite a few steep uphill sections and a sustained steep downhill section just prior to the last few miles which I was not prepared for. The other surprise for me was how many creeks there were to run though and how cold they were. Only a few single track sections where if you wanted to run up the hill you couldn’t as there was a line of people walking up. I suppose if you were speedy out the gate you’d be with other folks running up it though. Course was clearly marked. I thought the race guide said there was a bathroom at the half way aide station, but there was not. I held it, but it would have been nice to have some sort of bathroom at least once on course, as it’s pretty exposed so hard to just go ‘in the woods’. Cute shirt and medal. I guess there was some food at the end, but my kids were sick of waiting for me since it took me a long time and we left pretty quickly.
Great way to kick the devil's ankles
Second time running the 5k, but I volunteered the two years prior to the 5ks. All races start and end at Castle Rock Park in Walnut Creek at the base … MORE
Second time running the 5k, but I volunteered the two years prior to the 5ks. All races start and end at Castle Rock Park in Walnut Creek at the base of beautiful Mount Diablo. The 5k had ten (10) water crossings. These were not water crossings that you could jump over. These were stream crossing that you had to go through. Most were ankle to shin high. The water was COLD, too. The 5k measured 3.12 miles with 558 ft of elevation. There were some technical parts of the course, but the water was the most challenging aspect.
The 5k had one aid station that we saw twice. The 5k turnaround was just past the aid station and another stream crossing. Eager volunteers were there to hand out water and sports drink. I did not stop, but Brazen AS are stocked with sweet and salty snacks, Gu, and fruit.
All runners get a race shirt. 5k/10k get cotton and half marathoners get a technical fabric tee. The 50k runners get a special 50k shirt.
Brazen Racing medals are first rate and this one did not disappoint. As you crossed the finish line, Sam, the race director, called out your name. This is always special after a tough race.
There was food and drink at the finish as well as the traditional It’s It ice cream sandwich.
A special note about this race from the Brazen Racing website:
For over 40 years, Save Mount Diablo has worked tirelessly to preserve and increase the open space on and around Mount Diablo. In that time, their efforts have taken us from 6,788 acres of open space to over 100,000 acres of open space on and around the mountain!
With distances suitable for everyone from those hitting the trails for the first time to experienced ultra-runners, the Diablo Trails Challenge was created to help celebrate and support these achievements. A portion of all entry fees will go to Save Mount Diablo to help them continue preserving open space and trails for all of us to enjoy.
Awesome trail in the East Bay
This was my first trail race. I placed first in my age group and immediately signed up for a 37K and 100K - that's how inspiring this event was. There … MORE
This was my first trail race. I placed first in my age group and immediately signed up for a 37K and 100K – that’s how inspiring this event was. There was such a great group of runners! And they went all out feeding the runners after the race.
#BeBrazen
Beauty in the Devil
Want beautiful scenery? Check. Want a butt kicking challenge? Check. Want both, combined with support from an amazing racing organization? You got it. This race rocks, but be prepared. It’s … MORE
Want beautiful scenery? Check. Want a butt kicking challenge? Check. Want both, combined with support from an amazing racing organization? You got it. This race rocks, but be prepared. It’s tough.
Big Hills, Wet Feet
Don't shy away from the stream crossings—you will get wet, so go hard and gain over those who shy away. Same goes for the downhills. Often the uphills (which are … MORE
Don’t shy away from the stream crossings—you will get wet, so go hard and gain over those who shy away. Same goes for the downhills. Often the uphills (which are steep and long!) are single track, but the downhills are more wide open. I ran em hard—and shattered my legs, but, heck it’s racing!
Best race series around
Brazen races are hands down the best bang for your buck. The event is always well put together and has great swag/medals yet they still keep the entries priced fairly. … MORE
Brazen races are hands down the best bang for your buck. The event is always well put together and has great swag/medals yet they still keep the entries priced fairly. The crowd is always fun with some brim competitive and some just out there to do their first trail run.
Great race with brazen
Great race and great view of mount diablo. Met new people , nice friendly, raced with Forward Motions sports. Everyone should sign up for this race. MORE
Great race and great view of mount diablo. Met new people , nice friendly, raced with Forward Motions sports. Everyone should sign up for this race.
Wow that's a lot of climbing
If you like hills and you like beautiful views this is a good choice. Mt. Diablo offers really sweeping views of the Bay. Get ready for some hill climbing, but … MORE
If you like hills and you like beautiful views this is a good choice. Mt. Diablo offers really sweeping views of the Bay. Get ready for some hill climbing, but the good news is there’s a sweet downhill descent to balance it all out. Lots of Creek crossings to cool your tired feet. The finish line is basically a party of folks having fun eating and getting free massages!
First DNF Ever
It was a perfect day, and the trails were soft from rain but not muddy. This course has a lot of climb, but I stopped at the peak of Mount … MORE
It was a perfect day, and the trails were soft from rain but not muddy. This course has a lot of climb, but I stopped at the peak of Mount Diablo due to Shingles pain in my ear. I had a wonderful couple of miles with the amazing Catra Corbett and I missed one turn with a group of runners, but still give this course 5 stars since others were able to see the markings. (ok, only 4.98 stars, but I round up!) The RD gave me a half marathon medal since I ran 34.81 km on Garmin, and made it to Aid Station 4. I look forward to running this again next year!
Great Event and Trails
Aid stations are spaced out in great locations and there is a new view around every turn. Trails are mark and easy to follow, but they are very challenging from … MORE
Aid stations are spaced out in great locations and there is a new view around every turn. Trails are mark and easy to follow, but they are very challenging from start to finish. This is a must do at least one time, and I will do a repeat next time in the area.
Get to know Mt. Diablo
First 10k trail race. Nice challenge, a combination of fire trails, single track, stram crossings. Really fun! I loved seeing sections of the state park I had never visited. Good … MORE
First 10k trail race. Nice challenge, a combination of fire trails, single track, stram crossings. Really fun! I loved seeing sections of the state park I had never visited. Good aid stations.
Water Crossings and More
I bet this course this year had more water crossings then any year EVER!! What a perfect day for a perfect race. 22 stream crossings and trails that were spectacular … MORE
I bet this course this year had more water crossings then any year EVER!! What a perfect day for a perfect race. 22 stream crossings and trails that were spectacular = perfect race. I think we were even followed by a turkey. The volunteers and aid stations were spot on and the finish area was stocked to the gills. How can you say no to an IT’s IT? Come on, now.
Best runs in town!
If you ever want to run with an amazing company, Brazen Racing is THE BOMB! These guys seriously know how to execute a race. I've run many of their races … MORE
If you ever want to run with an amazing company, Brazen Racing is THE BOMB! These guys seriously know how to execute a race. I’ve run many of their races and plan to run many more. Many of their runs are trail and some are regular road races. They always offer a variety of distances to appeal to any level of runner: 5k, 10k, 13.1, 26.2 and even some 50k.
Brazen Racing knows how to do it right. Their courses are well marked, aid stations well stocked and their finish line food is second to none. One really cool thing, too, is their hardware. Brazen has some of the best, if not, the best race medals around. They really are worth running for. After all, it’s all about the medal, right?
Give them a run. You won’t be sorry you did.