Blue Sky Trail Marathon & Half Marathon

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

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.

The marathon boasts 3,500 feet of elevation gain/loss, while the half marathon checks in at 1,800 feet, and the route offers a little bit of something for everyone. It is designed to appeal to both veteran trail runners and those looking to experience their first trail racing adventure. The generous nine hour cut-off should ensure a successful day for everyone.

The course is 100% dirt and 90% sweet Colorado singletrack. The terrain ranges in difficulty from smooth dirt trail to technical rock gardens. A small portion of the route is on smooth dirt road (no motor vehicle access) and gravel bike path, with the meat of the running done on the beautiful and distinctive redstone hardpack of the Blue Sky Trail.

After the race, kick back and enjoy the always-popular barbecue and generous sponsor giveaways.

• 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
• Terrain: Marathon: 22mi dirt singletrack, 3mi rocky singletrack, 2mi dirt road; Half Marathon: 13.0mi dirt singletrack, 0.5mi dirt road
• Fauna: Deer, abert squirrel, golden eagle
• Registration Cap: 400 Marathon / 400 Half
• Time Allowance: 9 hours Marathon / 6 hours Half Marathon
• Dates: Marathon: Oct 17, 2026; Half Marathon: Oct 18, 2026

Registration

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

Marathon:
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:
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 in Return for Your Registration Fee:

• A beautiful, challenging and well-marked course on some of the best trails in Fort Collins
• Enthusiastic, knowledgeable race and aid station volunteers
• Fully stocked aid stations
• Free entry to Larimer County Open Space for the day
• Generous Cut-Offs (Marathon: 9hrs / Half 6hrs)
• Gender specific race T-shirt
• Unique finisher award and overall and age group awards
• Finish line meal
  
  • Vegetarian, vegan, gluten-free and non-alcoholic options are available as part of our standard race fare


• Professional medical and emergency communications

Waiting List

In the event that the race sells out, we will maintain a waiting list and transfer runners from the waiting list to the race roster should other runners already registered not be able to attend.

Transfer Credit Policy

If you are not able to race, we will be able to offer a race transfer credit that can be applied to any future Gnar Runners race (valid for 12 months). Credit deadlines are as follows:

Until March 31: 100% credit of registration (excluding RunSignup fees)
April 1 - July 31: 75% credit of registration (excluding RunSignup fees)
August 1 - October 15: 50% credit of registration (excluding RunSignup fees)

**In order to receive your credit, you must cancel your registration through the RunSignup registration platform.

Deferrals:

• Log in to your RunSignup account
• Go to Profile -> Upcoming Races -> Blue Sky -> Manage Registration
• At the bottom of the page, select “Defer Registration” and follow the automated process.
• While RunSignup will prompt you to, you DO NOT have to immediately choose which race to apply your credit to. Once you hit "Confirm Deferral" and see the "Your registration has been deferred" message, your credit is in the system and will be valid for one year past the event date.

Distance Switch:

• Log on to your RunSignup account
• Go to Profile -> Upcoming Races -> Blue Sky -> Manage Registration
• At the top, click the link to "Transfer Event"
• Follow the steps to register for the race in the new distance

Runners in the half marathon race can pay the additional registration fee to upgrade to the marathon race. There is no charge for marathon runners dropping down to the half marathon race.

The online deadline to transfer is Thursday (10/16) at midnight. It can also be done in person at packet pickup on Friday.

Cancellation & Refund Policy

Entries are non-refundable. Entries are non-transferable, except for transfers via the wait list. In the event the race is cancelled due to extreme weather, fire, disease or for some other unforeseeable event, we cannot offer refunds or credits.

Course & Aid Stations

Course Maps

Course GPX Files

• Blue Sky Marathon GPX (Current for 2025)
• Blue Sky Half Marathon GPX (Current for 2025)

Elevation Profiles

Marathon Aid Stations