Trail Running calendar near Longmont 2025-2026

Rock Hawk Trail Races, held at Philip S. Miller Park in Castle Rock, Colorado, offer four distances: 50K, 25K, 10K, and 5K. Runners traverse the rolling Miller Park and Ridgeline trails, described as gorgeous and thrilling but not overly technical, with sweeping views.The course provides a solid cha..

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..

Cirque Series returns to Arapahoe Basin, Colorado, for a high-alpine mountain race. On White River National Forest trails above Keystone, the course runs about 9 miles with roughly 2,411 feet of elevation gain, starting at Mountain Goat Plaza at the base of A-Basin. Racers ascend via summer road to..

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..

The Breckenridge Oktoberfest 5K is a festive trail run held in historic downtown Breckenridge, Colorado, as part of the annual Oktoberfest celebration. Scheduled for Saturday, September 13, 2025, the 5K course winds through the scenic Town of Breckenridge Trails, showcasing beautiful fall foliage an..

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..

The Greenland Open Space Pack Burro Race, presented by Double Rainbow Ranch, is the 4th annual event held in Larkspur, Colorado on the Greenland Open Space Trail. It offers two distances: 8 miles and 3 miles, raced by teams of one runner and one burro. The atmosphere blends friendly competition with..

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 is a multi-distance trail running festival at the YMCA of the Rockies in Granby, Colorado. Participants can choose from 50K, 33K, Half Marathon, 10K, and 5K, all on dirt trails with high-altitude scenery, rolling hills, and expansive mountain views. The 50K and 33K are..

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..

24 Hours of Palmer Lake is a 24-hour ultramarathon held in Palmer Lake, Colorado, on a 0.82-mile loop atop the Palmer Divide at about 7,240 feet elevation. The event is described as a low-fanfare, community-driven affair, welcoming runners who want to push mental and physical limits in a mountain se..

Castle Rock Trail Festival / liveBIG Run invites runners of all levels to explore Castle Rock’s ridgeline trails, including Philip S. Miller Park and Ridgeline Open Space, on Saturday, Oct. 4.Distances include a liveBIG Family Adventure Run (a family-friendly obstacle course), 5K, 10K, Ridgeline Tra..

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..