Diablo Trails Challenge
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Event details
The Diablo Trails Challenge takes place on April 4, 2026, at Mount Diablo with the event address listed as 1700 Castle Rock Road, Walnut Creek, CA, United States. The event is organized by Brazen Racing and is linked with the Save Mount Diablo organization; a portion of entry fees will be donated to Save Mount Diablo to support local open space and trail preservation. The event page lists race-day services such as volunteer support and volunteer photographers who provide free photos.
Distances and course information
The event offers the following race distances:
- 50K
- Half Marathon
- 10K
- 5K
The half marathon is part of the Brazen Ultra Half Series. The series notes that many of its half marathons measure slightly longer than 13.1 miles and feature significant ascents and descents on trail terrain. Registration pricing varies by distance and changes in stages; the event also lists a remote-runner option and an optional BBQ lunch ticket. Visit the organization's website for the most recent information.
