Diablo Trails Challenge

APR

4

2026

Take on Mount Diablo on April 4, 2026 with trail distances from 5K to 50K, including a challenging ultra half that often exceeds 13.1 miles. Organized by Brazen Racing, the event supports Save Mount Diablo and offers remote entries and post race photos.

Sat 4 Apr 2026

Walnut Creek, California

Website Registration

50 kilometers Half Marathon 10 kilometers 5 kilometers

Always double-check with the organizer's website! This page may contain affiliate links.

Diablo Trails Challenge : overview

The Diablo Trails Challenge is a trail running event on Mount Diablo held on April 4, 2026, at 1700 Castle Rock Road, Walnut Creek, CA, United States. The event offers multiple race distances on mountain trails.

Distances

50K
Half marathon
10K
5K

There is also a remote runner option and a separate BBQ lunch ticket.

Additional details

The event is organized by Brazen Racing and is associated with the Brazen Ultra Half Series; the half marathon is described as an "ultra-half" with courses that often exceed 13.1 miles and include significant ascents and descents. A portion of entry fees will be donated to Save Mount Diablo to support preservation and trail efforts on and around the mountain.

Registration fees are tiered and increase as the event approaches. Official race results and free photos from volunteer photographers are made available after the event. Volunteer roles are listed for those who wish to support the race. Visit the organization's website for the most recent information.

50 km

50k

Half Marathon

1/2 Marathon

10 km

10k

5 km