Diablo Trails Challenge
Walnut Creek, United States • 4 Apr 2026
The Diablo Trails Challenge is a trail running event held at 1700 Castle Rock Road, Walnut Creek, California. It offers multiple race distances including a 50K ultra, half marathon, 10K, and 5K, catering to both beginners and experienced ultra-runners. The event celebrates and supports the preservation of Mount Diablo's open spaces, with a portion of entry fees benefiting Save Mount Diablo, an organization dedicated to protecting over 100,000 acres of natural land around the mountain. The challenge provides a scenic and rewarding experience on well-maintained trails, promoting outdoor recreation and conservation efforts in the region. Visit the organization's website for the most recent information.