Blue Sky Trail Marathon & Half Marathon – Fort Collins, CO 2026

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 o