Blue Sky Trail Marathon & Half Marathon

Welcome

Welcome to the Blue Sky Trail Marathon & Half, Fort Collins's original and only trail marathon.

Course Description

Taking place on the trails between Horsetooth Mountain Park and the Devil's Backbone Open Space, the course takes you on a north-south tour of the easternmost hogbacks of Northern Colorado's mighty Front Range.

• Elevation Gain/Loss: 3,500 feet for the marathon, 1,800 feet for the half marathon.
• Cut-Off Time: A generous nine hour cut-off should ensure a successful day for everyone.
• Terrain: 100% dirt with 90% sweet Colorado singletrack, with terrain ranging from smooth dirt trail to technical rock gardens.
• Post-Race: After the race, kick back and enjoy the always-popular barbecue and generous sponsor giveaways.

Location

• Start: Blue Sky Trailhead, Horsetooth Mountain Park, Fort Collins, Colorado
• Distance: 26.7 miles (3,500') or 13.4 miles (1,800')
• Min/Max Elevation: 5,300'-6,500'
• Average Elevation: 5,700' Marathon

Registration

Fees for the 2026 Blue Sky Marathon & Half Marathon are as follows:

• Marathon Fees: Dec 15 – Feb 28: $110 + $7.60 fee: March 1– June 30: $120 + $8.20 fee: July 1 – Oct 17: $130 + $8.80 fee: Packet Pickup: $145
• Half Marathon Fees: Dec 15 – Feb 28: $90 + $6.40 fee: March 1– June 30: $100 + $7.00 fee: July 1 – Oct 17: $110 + $7.60 fee
• What You Get: A beautiful, challenging and well-marked course on some of the best trails in Fort Collins, fully stocked aid stations, free entry to Larimer County Open Space for the day, and more.

Course & Aid Stations

Course Maps

• Marathon Map
• Half Marathon Map

Marathon Aid Stations

List of aid stations along the marathon course with mile splits and cut-offs.

Half Marathon Aid Stations

List of aid stations along the half marathon course with mile splits.

All aid stations will offer Gnarly Nutrition Fuel2O sports drink, Hammer Gels, water and soda plus a variety of salty and sweet bites, and a selection of fruit.

Race Rules

Race rules are designed to provide a safe and fair experience for everyone involved.

1. The marathon will be limited to 9 hours, and the half marathon will be limited to 6 hours.
2. At each aid station, volunteers will record runner bib numbers. Runners must ensure their number is recorded.
3. Purposeful littering is prohibited and will result in immediate disqualification.

Schedule

Friday 10/16:

• 4:00-7:00p: Optional marathon & half marathon packet pick-up at Altitude Running.

Saturday 10/17:

• 5:30-6:45a: Marathon Race Day Packet Pickup
• 7:00a: Marathon Start

Sunday 10/18:

• 5:30-6:45a: Half Marathon Race Day Packet Pickup
• 7:00a: Half Marathon Start

Parking & Directions

Marathon

• The Marathon Start/Finish line is located at the Blue Sky Trailhead.
• The parking for participants will be located in the Inlet Bay Marina parking lot.

Half Marathon

• The Half Marathon Start/Finish line is located at the South Bay Pavilion.
• Parking for participants will also be in South Bay.

Link to Register

To register for the race, visit this registration page.