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Diablo Summit Stomp

Walnut Creek, United States • 18 Oct 2025

Event overview

The Diablo Summit Stomp takes place on October 18, 2025 in Walnut Creek, California (1700 Castle Rock Road). Distances offered are:

  • 30K
  • Half Marathon
  • 10K
  • 5K

All distances are run on dirt trails in Castle Rock Park and Mount Diablo State Park. The 30K route reaches the summit of Mount Diablo. Walkers and hikers are welcome on all distances. Age-group awards are given to the top three finishers in five-year categories, with smaller categories for younger ages.

Course and race details

Courses are marked with colored ribbons, signs, and flour. Course maps, elevation charts, and GPX files are provided for each distance so participants can follow routes on a phone or watch. The 30K has an overall time limit of 6.5 hours and the event uses on-course cut-offs at aid stations located at about mile 9, mile 12, and mile 15. 30K runners may be allowed to switch to the half marathon at Aid Station #3 under a timing condition; those who switch are counted as finishers of the half but are not eligible for overall or age-group awards and will be listed in a surrender category.

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. Half marathon runners are encouraged to be cupless; volunteers will refill containers and a collapsible Hydrapak Speed Cup is available for purchase. Visit the organization's website for the most recent information.

United States California Walnut Creek

Race information

Website Registration
30 km
30k
21 km
Half Marathon
10 km
10k
5 km
Visit the organization's website for the most recent information.
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