Trail Running calendar near Fort Collins 2025-2026

Front Range Ultra Dayze is a multi-day ultra-running festival in Loveland, Colorado, centered at Centennial Park and the River’s Edge Natural Area. Event distances range from 200-mile to 50k, plus timed formats up to 100+ hours, with a 200-runner cap. The flat, fast 2-mile loop traverses mostly dirt..

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

American Heroes Run takes place in Longmont, Colorado, on a flat, fast loop course of about 1.05 miles. The event features multiple distances, including a 100-mile race (with a 30-hour cutoff), a 24-hour option, marathon, half-marathon, 9.11-mile, and 5K, plus shorter time-limited runs. The atmosphe..

The HRCA Wildcat Mountain Trail Races, held in Littleton, Colorado, offer a scenic and challenging trail running experience through the HRCA Backcountry Wilderness Area. Participants can choose from a 10-mile or 10-kilometer course, both featuring 100% dirt trails with varied terrain and stunning mo..

Black Squirrel Half Marathon is a trail race held at Lory State Park, northwest of Fort Collins, Colorado, with the start and finish at the Soldier Canyon Picnic Area in Bellvue. The 13.5-mile course tour climbs about 1,500 feet to a west ridge around 7,000 feet, then descends and follows roughly 4...

RexRun for PAWSitivity is a pet-friendly trail event in Aurora, Colorado at the Arapahoe County Fairgrounds. It offers a 5K Trail Run, a Family 5K Trail Walk (dogs welcome) and a Kids 1-mile Run/Walk. The day features a pet-centric atmosphere with therapy and patrol K-9 demonstrations, a dog costume..

Devil on the Divide is a trail ultramarathon held in Empire, Colorado, offering two distances: 50K and 22K. The 100% dirt, point-to-point courses traverse stunning, remote terrain with views of Clear Creek County and the Continental Divide, reaching elevations above 13,000 feet. The 50K features abo..

Nestled in Old Town Nederland, Colorado (elevation around 8,236'), NedNed Trail Fest offers a long-running trail challenge with three race options: a Half Marathon (about 13.3 miles with roughly 1,408 feet of elevation gain on dirt roads and single-track trails), a 10K (about 6.3 miles on dirt roads..

Jelm Mountain Run, held near Jelm, Wyoming, offers a 10-mile out-and-back and a 50k (three laps of the same course). The route climbs from about 7,618 feet to the Infrared Observatory atop Jelm Mountain at over 9,600 feet, with more than 2,000 feet of total elevation gain, on improved jeep roads wit..

Snow Mountain Ranch Trail Race, held at the YMCA of the Rockies in Granby, Colorado, offers distances for all levels: 50K (31.4 miles), 33K (20.2 miles), Half Marathon (12.8 miles), 10K (6.1 miles), and 5K (3.3 miles). The courses are 100% dirt, featuring out-and-back and looping designs through rol..

Demon Dash is a 5K running or walking event held in Arvada, Colorado, featuring a new dirt course at the NAAC for a fresh home and surface. It’s pitched as a fun, community-focused experience suitable for runners and walkers of all ages. This year, the race runs in conjunction with the Demons Invite..

The Frederick Pack Burro Race is an annual 10K event held in Frederick, Colorado, celebrating the town's Miners Day heritage. The race follows a scenic course starting downtown at Fifth and Oak Streets, heading north along a trail through a tunnel to the Frederick Recreation Area, looping around Mil..

Red Feather Trail Jamboree is a three-day trail running weekend held near Red Feather Lakes, Colorado, starting from the Ben Delatour Scout Ranch. Runners can tackle three distances: 50 miles (≈8,500 ft of gain), 50K (≈4,200 ft), and a Half Marathon (≈1,700 ft), with a 3-day Challenge totaling about..

Estes Epic is a multi-event trail challenge held in Estes Park, Colorado. The weekend features a 50k bike race, a 50k trail run, a Heavy Half Marathon, and the all-in Epic Double (50k MTB and 50k Run). After a six-year break, the race returns with remote, rugged terrain, single-track trails, steep c..

Rocky’s Backyard Ultra is held at the YMCA of the Rockies Estes Park Center in Estes Park, Colorado. Runners must complete 4.167 miles in under one hour each lap, with the field reduced to a single finisher as the race continues until no others remain. The course loops around the boundary of RMNP on..

The Bear Chase Race Endurance Festival unfolds at Bear Creek Lake Park in Lakewood, Colorado, and offers six races: 100K, 50 Mile, 50K, Half Marathon, 10K, and 5K (with a Baby Bear 10K variant). The mostly dirt, single-track course is described as fast by trail standards and not overly technical, wi..

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..

Blue Sky Trail Marathon & Half takes place in Fort Collins, Colorado, on the trails between Horsetooth Mountain Park and the Devil’s Backbone Open Space. Runners choose between the Blue Sky Marathon (26.7 miles with about 3,500 feet of elevation gain/loss) and the Blue Sky Half (13.4 miles with abou..

Beware The Bear Trail Races take place at Bear Creek Lake Park in Lakewood, Colorado. The event offers four distances: 5K, 15K, a 5K+15K double, and a Kids 1K race. The courses are mostly dirt, using single and double-track trails with short, steep climbs, rollers, and rugged terrain, providing a so..

Colorado 24 Hour Run takes place in Fort Collins, Colorado, at 4927 E. County Road 36. The event offers multiple distance options: 24-hour, 12-hour, and 6-hour races, plus 24-hour, 12-hour, and 6-hour relays.Runners complete laps on a one-mile dirt loop—the flat, scenic loop you’ll find in Colorado—..