Blue Sky Trail Marathon

Fort Collins, United States • 17-18 Oct 2026

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.

Race information

27 mi
Marathon
13 mi
Half Marathon
Visit the organization's website for the most recent information.
Trail runs nearby

Repeating 2 km out and back laps on the Thumb Open Space trail in Estes Park. Participants collect a poker chip at each turnaround and the most chips wins during a sunup to sundown timeframe; 35 spots and a $100 entry fee.

An overnight team relay covering 200 miles and 36 legs from Fort Collins to Steamboat Springs, crossing two mountain passes. Multiple team categories are offered and teams choose between supplying volunteers or donating to Windsor Gives.

A four-race midweek trail series in August at Lory State Park near Fort Collins with distances from 5k to 12k, chip timing, series points and awards. Vintage shirts, pizza and beverages follow each race.

A hilly 10 km trail race at Lory State Park's Eltuck Picnic Area with 1,700 feet of elevation gain and a 100-runner cap. The event includes pre-attached timing chips, no on-course aid, and post-race pizza and beverages.

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