Blue Sky Trail Marathon & Half Marathon Fort Collins, CO   Oct 18–19, 2025

Taking place on the trails between Horsetooth Mountain Park and the Devil’s Backbone Open Space, the Blue Sky courses take you on a north-south tour of the easternmost hogbacks of Northern Colorado’s Front Range mountains. With a moderate amount of elevation gain and loss and a variety of terrain, 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 cut-offs 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 dirt road (no motor vehicle access) and gravel trail, 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 BBQ, awards and generous sponsor giveaways.