Blue Sky Trail Marathon
Fort Collins, United States • 17-18 Oct 2026
Blue Sky Marathon & Half
The Blue Sky Trail Marathon and Half Marathon take place on the easternmost hogbacks of Northern Colorado’s Front Range mountains. The courses run through the trail systems between Horsetooth Mountain Park and the Devil’s Backbone Open Space near Fort Collins. The routes consist primarily of dirt singletrack with some sections of rocky terrain and dirt roads.
Participants can choose from two distances held on separate days:
- 26.7 miles with approximately 3,500 feet of elevation gain.
- 13.4 miles with approximately 1,800 feet of elevation gain.
The terrain varies from smooth dirt hardpack to technical rock gardens. The marathon course includes 22 miles of dirt singletrack, 3 miles of rocky singletrack, and 2 miles of dirt road. The half marathon course is composed of 13 miles of dirt singletrack and 0.5 miles of dirt road. Both distances feature generous time allowances, with 9 hours for the marathon and 6 hours for the half marathon.
Aid stations are located along the course providing fluids, gels, and various snacks, including vegetarian and vegan options. The event follows Trail Sisters Approved Standards. Registration includes a park pass for Larimer County Open Space, a race shirt, a finisher award, and a post-race meal. The field is limited to 400 runners per distance. Visit the organization's website for the most recent information.