Trail Running Calendar Colorado 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..

Creede Mountain Run, held in Creede, Colorado, offers four distances: 2 miles, 12 miles, 22 miles, and 50K. The race begins in the historic mining town and climbs Willow Creek, passing old mines perched on vertical cliffs near the Black Pitch. The 12-mile course completes the Bachelor Loop, while th..

The Grand Traverse Mountain Run is a 40-mile, point-to-point ultra from Crested Butte to Aspen, Colorado, climbing the Elk Mountains with more than 6,000 feet of elevation gain. It follows the Grand Traverse Backcountry Ski race route and is run as a fundraising event for Crested Butte Nordic. The c..

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..

The Rock Hawk Trail Races take place at Philip S. Miller Park in Castle Rock, Colorado, featuring distances of 50K, 25K, 10K, and 5K. The event is held on the scenic, rolling trails of Miller Park and the Ridgeline Trail systems, offering a course that is not overly technical but still challenging a..

Summer Predictor SERIES - Derek Lindstrom is a fundraising running series featuring prediction games tied to two summer races. For 2025, events take place in Leadville, Colorado, and Marquette, Michigan, with the Leadville Trail Marathon (26.2 miles) and the Marquette Half Marathon (13.1 miles). Par..

The Sneffels Round, organized by Sky Pilots Endurance Navigators, is a free mountaineering endurance challenge based in Ouray, Colorado. Participants race the 100-hour clock by building their own route through roughly 39 peaks, including Mt. Sneffels, with several elective options that let finishers..

The 10k @ 10,000 Feet is a challenging trail running event held at the summit of Rabbit Ears Pass near Steamboat Springs, Colorado. Known for its breathtaking mountain scenery, the race features a course starting at 10,000 feet elevation, with about 1,200 feet of elevation gain and loss. The main ra..

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..

52nd Annual Imogene Pass Run takes place in Telluride, Colorado. The challenging mountain race runs from Telluride over Imogene Pass to a finish in Telluride, with aid stations along the way. The course includes a summit at mile 10 and a Tunnel Station at mile 15.5, and organizers describe it as an..

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..

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..

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...

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..

Run Rabbit Run in Steamboat Springs, Colorado, features 100- and 50-mile ultramarathons through Routt National Forest and Emerald Mountain. The 50-mile course starts at the Steamboat ski area and climbs to Mount Werner, crosses the Continental Divide to Rabbit Ears Mountain, then returns, with about..

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..

The Ouray 50 Mile Endurance Run, held in Ouray, Colorado, is a challenging mountain ultramarathon featuring approximately 23,582 feet of elevation gain. Known for its technical and demanding trails, the course is set nearly two miles above sea level amidst stunning mountain scenery. The race is desi..

Trail Sisters Women's Half Marathon & 10k takes place in Buena Vista, Colorado, tucked in the Rocky Mountains along the Arkansas River. The events include a 13.1-mile trail half marathon and a 10k. The courses wind through sagebrush and ponderosa pines, rewarding runners with views of the Collegiate..

Blisters & Brews is a 5k fundraiser race held in Telluride, designed for attendees of the Telluride Blues & Brews Festival to enjoy a morning of exercise before the festivities begin. The event supports the Telluride Adaptive Sports Program and features a scenic route that includes views of Bridal V..