Diablo Trails Challenge
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Diablo Trails Challenge
The Diablo Trails Challenge is a trail running event on Mount Diablo organized by Brazen Racing on April 4, 2026. It takes place at 1700 Castle Rock Road, Walnut Creek, CA, United States. The event is part of the Brazen Ultra Half Series, and half marathon runners are invited to participate in the series. A remote runner option and a paid BBQ lunch plate are listed as registration options. A portion of all entry fees will go to the nonprofit Save Mount Diablo to support preservation of open space and trails.
Race distances and event details
- 50K
- Half Marathon
- 10K
- 5K
Registration fees are shown by distance and increase at set dates before the event. Volunteer photographers provide free event photos, and official results are posted after the race. Sponsors named for the event include GU and Salus. Additional event information on bib pick-up, course maps, FAQs, and volunteer opportunities is listed by the organizer. Visit the organization's website for the most recent information.