Run Boulderthon: The Boulder Marathon
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Event overview
Boulderthon is an annual running festival held in Boulder, Colorado, staged in the foothills of the Rockies. The series includes a full marathon and multiple shorter races and events. The event is USATF sanctioned, measured by a Level A USATF Course Measurer, and accepts Boston Marathon qualifying performances. Organizers report large participation levels in recent years, with over 10,000 finishers in 2024 and about 15,000 athletes and attendees noted at a recent edition. The 6th annual Boulderthon is scheduled for Sunday, September 27, 2026.
The event program includes an expo, VIP offerings, course entertainment, pacing groups, and an after party. Organizers have published new course maps that return to earlier routing near the reservoir and reduce elevation gain by an estimated 40-50 percent.
Course, races, and recognition
The race routing highlights views near Boulder Reservoir and a Start and Finish in downtown Boulder, with a finish on Pearl Street Mall noted in course descriptions. Multiple distances are offered within the festival format, including:
- Marathon
- Half Marathon
- 10K
- 5K
- Kids Run
Boulderthon has received national recognition from media outlets and running publications, including placements on lists by USA Today, Runner's World, and Active. Recent participant feedback and review scores report strong marks for location, safety, course navigation, and event communication. Visit the organization's website for the most recent information.