Diablo Trails Challenge
Walnut Creek, United States • 4 Apr 2026
Diablo Trails Challenge (April 4, 2026)
The Diablo Trails Challenge is a trail running event on Mount Diablo near Walnut Creek, California. It is organized by Brazen Racing and takes place on April 4, 2026 at the Castle Rock Road venue (1700 Castle Rock Road, Walnut Creek, CA). The event includes multiple race distances held the same day and is part of the Brazen Ultra Half Series for half marathon entrants. The race supports Save Mount Diablo; a portion of entry fees will go to that organization. The Save Mount Diablo effort is described as having increased open space on and around Mount Diablo from 6,788 acres to over 100,000 acres and has operated for more than 40 years.
Distances and entry
- 50K
- Half Marathon
- 10K
- 5K
Registration fees are tiered by date. Example current prices listed include: 50K $159.17, Half Marathon $105.80, 10K $86.58, 5K $76.98, Remote Runner $50.29, and a BBQ lunch plate $23.60. Remote runner registration is offered as an option and a BBQ ticket is available for purchase. Course information, bib pick-up details, results, photos, and volunteer opportunities are provided by the organizer. Visit the organization's website for the most recent information.