All-Out Fall Fest

All-Out Fall Fest is a multi-distance running event in Westminster, Colorado at Church Ranch Office Park on Saturday, September 13, 2025. Participants choose from Half Marathon, 10K, 5K, or virtual versions of the half, 10K, and 5K. The course winds southwest along the Big Dry Creek Trail, with Standley Lake and the Flatirons in view.

The event evokes 70s nostalgia and flower power, and is an official BOLDERBoulder qualifier. Proceeds benefit #themarshalleffect, a charity supporting youth mental health. The race is part of the Endless Series with Beat the Heat, and offers discounts for signing up for multiple distances. Visit the organization's website for the most recent information.