Trail Running calendar near Fort Collins 2025-2026

The Eltuck Valley 12K is part of the Lory Summer Trail Series held at Lory State Park in Bellvue, Colorado. This midweek trail race series offers distances ranging from 5K to 12K, catering to both new and experienced trail runners. The August 26 race features a fast and flat 12K course along the Val..

Front Range Ultra Dayze is an ultra-running festival held in Loveland, Colorado, featuring a variety of ultra-distance events including 50k, 100-mile, 200-mile, and timed races from 12 to 100 hours. The course is a flat, fast 2-mile loop with 80% dirt trail and 20% pavement, set in Centennial Park a..

The Calarat Challenge Trail Running Festival takes place in Jamestown, Colorado, at the scenic Cal-Wood Education Center and Balarat Outdoor Education Center. Held over Labor Day weekend, the event features multiple trail races including a half marathon, 10K, 5K, Kids 1K, and combination races like..

The American Heroes Run, held in Longmont, Colorado, is a patriotic running event commemorating the events of 9/11. It features a variety of distances including a 100-mile ultra, marathon, half-marathon, 9.11-mile run, 5K, and timed runs such as 24-hour and 6-hour options. The race takes place on a..

The HRCA Wildcat Mountain Trail Races take place in Littleton, Colorado, starting at the Douglas County East/West trailhead near Rocky Heights Middle School. The event features 10K and 10-mile trail races along the scenic HRCA Backcountry Wilderness Area Wildcat Mountain trail system, offering 100%..

The Black Squirrel Half Marathon is a 13.5-mile trail race held in Lory State Park near Fort Collins, Colorado. Featuring approximately 2,000 feet of elevation gain and loss, the course offers a challenging yet accessible experience on a mix of dirt singletrack and road terrain. Runners ascend nearl..

Devil on the Divide is a challenging trail running event held in Empire, Colorado, featuring 50K and 22K point-to-point courses. Set against the stunning backdrop of Clear Creek County and the Continental Divide, the race offers breathtaking views and high-altitude terrain, with the 50K course reach..

The Jelm Mountain Run, held in Southeast Wyoming near Jelm Mountain, offers two challenging race distances: a 10+ mile out-and-back course and a 50k, which is three loops of the 10-mile route. The course features rugged jeep roads with over 2,000 feet of elevation gain, starting at 7,600 feet and cl..

The Ned Ned Half Marathon is a long-standing trail running event held in Nederland, Colorado, a picturesque mountain town at 8,236 feet elevation. Celebrating over 43 years, the race features a challenging 13.3-mile half marathon with 1,408 feet of elevation gain, traversing dirt roads and single-tr..

Snow Mountain Ranch Trail Running Festival, held in Granby, Colorado, offers a scenic and challenging trail running experience with race distances of 50K, 33K, Half Marathon, 10K, and 5K. Set at the YMCA of the Rockies, the courses feature 100% dirt trails winding through rolling hills, golden aspen..

The Red Feather Trail Jamboree is a three-day trail running event held at Ben Delatour Scout Ranch in Red Feather Lakes, Colorado. Scheduled for September 26-28, 2025, it offers three race distances: a 50-mile ultra with 8,500 feet of elevation gain, a 50K with 4,200 feet gain, and a half marathon f..

Rocky's Backyard Ultra is a unique ultra trail race held at the YMCA of the Rockies in Estes Park, Colorado, known as the highest organized Backyard Ultra in the world. Runners complete 4.167-mile laps on a challenging singletrack course featuring about 500 feet of elevation gain and loss per lap, w..

The Bear Chase is an endurance trail race festival held at Bear Creek Lake Park in Lakewood, Colorado. It offers multiple distances including 100K, 50 Mile, 50K, Half Marathon, 10K, and 5K, making it suitable for both first-time ultramarathoners and experienced trail runners. The course features mos..

The Blue Sky Trail Marathon & Half Marathon, held in Fort Collins, Colorado, offers a scenic and challenging trail running experience through Horsetooth Mountain Park and Devil’s Backbone Open Space. The marathon covers 26.7 miles with 3,500 feet of elevation gain, while the half marathon spans 13.4..

The Great Trailhead Foot Race 10 Miler takes place at Bear Creek Lake Park in Lakewood, Colorado, offering runners a scenic trail experience with single-track dirt paths against the backdrop of Denver's skyline. Participants can choose between a 5-mile or a challenging 10-mile double-lap course. Reg..

Beware The Bear Trail Races take place at Bear Creek Lake Park in Lakewood, Colorado, offering 5km, 15km, and a combined 5+15km double race, along with a 1km kids' run. The courses feature mostly dirt trails with a mix of single and double tracks, incorporating short steep hills, rollers, and varied..

The Colorado 24 Hour Run, held in Fort Collins, Colorado, offers a unique endurance running experience on a scenic, flat one-mile dirt loop. Participants can challenge themselves in various timed events including 6, 12, and 24-hour runs, as well as relay options for each duration. The course is desi..

The BINGO! Trail Party is a unique trail running event held at May Farms in Byers, Colorado. It offers multiple distance levels ranging from 6 to 54 miles, with a distinctive bingo-style format where runners complete loops and mark numbers on their bibs based on bingo balls drawn after each loop. Th..

The HRCA Backcountry Wilderness Half Marathon is an annual 13.1-mile trail race held in Highlands Ranch, Colorado, featuring a scenic single-loop course through the Douglas County East/West trail and the Backcountry Wilderness Area. The race offers a challenging route on dirt, gravel, and singletrac..

The Louisville Trail Race, held annually in Louisville, Colorado, features a Half Marathon, 10K, and 5K, attracting runners to the scenic front range trails. Celebrating its 12th year, the event offers mostly dirt trail courses with some bike path sections, showcasing the stunning Flat Irons and fro..