Diablo Summit Stomp
Walnut Creek, United States • 18 Oct 2025
Distances
- 30K - includes route to the Mount Diablo summit
- Half Marathon
- 10K
- 5K
Course and race information
The Diablo Summit Stomp takes place on October 18, 2025, at Castle Rock Park in Walnut Creek, California, with courses entering Mount Diablo State Park. All distances are on dirt trails and the 30K reaches the summit. Walkers and hikers are welcome in every distance. Age group awards are given to the top three finishers in five-year categories, with smaller categories for younger ages.
Courses are marked with colored ribbons, signs, and flour. Organizers provide GPX files and course maps for runners to follow. Water stations are stocked with water, sports drink, gels, pretzels, and candy. Runners in the 10K, half marathon, and 30K are recommended to carry at least two bottles or a large hydration pack. The event requests that half marathon runners be cupless when possible; volunteers will refill containers and can provide cups if needed. The 30K has an overall time limit of 6.5 hours and on-course cut-offs at aid stations. 30K runners who switch to the half marathon at Aid Station #3 are recorded as half marathon finishers but are not eligible for overall or age group awards and are listed in the "surrender" category. Visit the organization's website for the most recent information.