Blue Sky Trail Marathon

Event

The Blue Sky Trail Marathon & Half Marathon is a trail race in Fort Collins, Colorado, on October 17-18, 2026. The course runs between Horsetooth Mountain Park and the Devil’s Backbone Open Space, starting at the Blue Sky Trailhead. Distances offered:

• 26.7 miles (approx. 3,500 ft elevation gain/loss)
• 13.4 miles (approx. 1,800 ft elevation gain/loss)

Min/max elevation on course is listed as 5,300 ft to 6,500 ft; the marathon average elevation is 5,700 ft. Registration is capped at 400 runners for each distance.

Course and logistics

The route is 100% dirt and about 90% singletrack, with sections described as smooth dirt, technical rock gardens, a few miles of rocky singletrack, and short stretches of dirt road or gravel trail. The marathon course includes marked aid stations and intermediate cut-offs; overall time limits are 9 hours for the marathon and 6 hours for the half marathon. Aid stations provide sports drink, gels, water, soda, fruit and salty and sweet foods, with gluten-free and vegan alternatives available. Runners must carry at least 16 oz of water capacity; there are no aid station water cups. Courses will be marked with pink flagging, pin flags and flour at key intersections. Crewing and pacing rules differ by distance: pacers are not allowed and crewing is permitted only at designated aid locations. Toilets and drop-bag procedures are provided at start/finish and some aid stations. Visit the organization's website for the most recent information.