Diablo Summit Stomp
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Diablo Summit Stomp - Walnut Creek, October 17, 2026
The Diablo Summit Stomp is a trail race held on October 17, 2026, in Walnut Creek. The event offers four distances on dirt trails that start at Castle Rock Park and travel into Mount Diablo State Park, with the 30K route reaching the summit.
Distances
- 30K course to the summit in Mount Diablo State Park
- Half Marathon mostly on dirt trails through Castle Rock and Mount Diablo
- 10K on marked dirt trail routes
- 5K on dirt trails within Castle Rock and Mount Diablo
Each course is marked with colored ribbons, signs, and flour. Course maps and elevation charts are provided and GPX files are available for download so runners can follow routes on a phone or watch. Runners unfamiliar with the courses are advised to carry a copy of the map.
The 30K has an overall time limit of 6.5 hours and there are on-course cut-offs at designated aid stations. Runners who change distances mid-race under the event rules will be scored for the distance they finish but may not be eligible for awards and may be listed in a surrender category. Half marathon participants must meet the aid station cut-off or may be transported back to the start.
Water stations stock water, sports drink, gels, pretzels, and candy. Runners in the longer distances are advised to carry at least two bottles or a large hydration pack. The event encourages cupless running where possible and volunteers will refill containers or provide cups if needed. A collapsible Hydrapak Speed Cup may be available for purchase at the merchandise tent. Visit the organization's website for the most recent information.
