Blue Sky Trail Marathon

OCT
17-18
2026
Trail marathon and half near Fort Collins along redstone singletrack and technical rock sections, with stocked aid stations, drop bag options, and caps of 400 entries per distance.
17-18 Oct 2026
27 miles 13 miles

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Blue Sky Trail Marathon and Half

The Blue Sky events are trail races held around Horsetooth Mountain Park and the Devil's Backbone Open Space near Fort Collins, Colorado. Courses run roughly north to south along the easternmost hogbacks of the Front Range and include varied singletrack and some dirt road.

Distances include:

  • 26.7 miles, approximately 3,500 ft total elevation gain
  • 13.4 miles, approximately 1,800 ft total elevation gain

Course details: the route is 100% dirt and about 90% singletrack. Terrain ranges from smooth dirt trail to technical rock gardens on redstone hardpack. Minimum and maximum elevations are about 5,300 ft to 6,500 ft; average marathon elevation is about 5,700 ft. The marathon route breakdown lists 22 miles of dirt singletrack, 3 miles of rocky singletrack, and 2 miles of dirt road. The half course lists about 13.0 miles of dirt singletrack and 0.5 miles of dirt road.

Support and logistics: field aid stations are fully stocked with sports drink, gels, water, soda, snacks and fruit; gluten free and vegan alternatives are available by request. Drop bags are permitted at designated start/finish locations. Registration is capped at 400 entries per distance and time allowances are 9 hours for the marathon and 6 hours for the half. Event rules require a minimum personal water carry and prohibit dogs and pacers. Visit the organization's website for the most recent information.

27 mi
Marathon
13 mi
Half Marathon
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