Blue Sky Trail Marathon

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..

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...

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..

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—..

Thumbs Up Vertical Challenge takes place in Estes Park, Colorado, on December 6, 2025. The race uses the Thumb Open Space trail, a 2km out-and-back course with 540 feet of vertical gain per lap. The route is 100% single-track with switchbacks, steps and steep rocks, offering views of Longs Peak, Mou..