Trail Running calendar near Longmont 2025-2026

The Vail Ultra Benefiting 50 For The Fallen is a 50-mile ultra running event held at The Hangout at Golden Peak in Vail. This challenging race is part of the VVF Summer Mountain Games and supports the 50 For The Fallen organization. The event offers a competitive and inspiring atmosphere for men, wo..

The adidas Terrex Après 5K Trail Run is a spirited evening trail race held on Vail Mountain, starting and finishing at Nature Valley Mountain Plaza in Vail Village. This 5-kilometer course features diverse terrain including forest service dirt roads, rocky paths, grass, loose gravel, and undulating..

The adidas TERREX 10K Spring Runoff is a challenging trail running event held in Vail, Colorado, at nearly 9,000 feet elevation. Participants race on the scenic Vail Mountain trails, navigating a course with constant elevation changes and diverse terrain including dirt roads, rocky paths, grass, loo..

The Summits Trail Runs, part of the Human Potential Running Series, take place at Granby Ranch Resort in Colorado's Rocky Mountains. This event offers multiple trail running distances: Single (6 miles), Double (21 miles), Triple (27 miles), and Quad (43 miles), plus a unique 32-hour Elevation Challe..

The Barr Lake Trail Race, held in Brighton, Colorado, offers a scenic and fast trail running experience around Barr Lake State Park. Celebrating its sixth year, the event features multiple distances: 50K, 30K, half marathon, 15K, and 5K, all on flat, dirt terrain with minimal elevation gain (under 1..

Estes Park's Backyard Ultra is a unique ultramarathon held in Estes Park, Colorado, featuring scenic views of Lake Estes. Participants run a 4.252-mile loop on a paved bike trail with a 150-foot elevation gain per lap at 7,522 feet elevation. The race follows the Backyard Ultra format, where runners..

The Sunset Trail Running Festival, taking place in Gold Hill, Colorado, features a variety of trail races including a 28K, 12K, 5K, and a Kids 1K. This event, organized by The Boulder Watershed Collective and T.E.A.M Boulder, aims to raise funds for wildfire preparation and community resilience init..

The Midsummers Night Run is a 10K race held in Winter Park, Colorado, starting and finishing at the base of Winter Park Resort. The course features a mix of gravel roads and trails with an elevation gain of approximately 570 feet, offering a scenic and moderately challenging route. This event is par..

The Timberview Trail Run is an annual trail running event held at Lory State Park in Bellvue, Colorado. Celebrating its sixth year in 2025, the race offers three distances: 5K, 5 mile, and 10 mile, catering to all levels of athletes including beginners and children. The scenic courses wind through f..

Chase the Moon is a unique overnight ultramarathon held in Highlands Ranch, Colorado, featuring a 12-hour solo and team relay format under the full moon. The event offers various distances including 12-hour solo, 3- and 5-person relays, 6-hour and 3-hour solos, and a 50K race. Runners traverse a sce..

The Silverheels Trail Runs, hosted by the Human Potential Running Series, is a premier ultra running event held in Como, Colorado, featuring breathtaking high-altitude courses averaging over 10,000 feet. The event offers multiple distances including 10-Mile, 19-Mile, 60k, 50-Mile, 100k, and a challe..

The Never Summer 100km and 60km trail races take place in State Forest State Park, Colorado, between the Never Summer Mountains near Rocky Mountain National Park and the Medicine Bow Mountains north of Cameron Pass. The event offers ultra-distance mountain running with challenging terrain including..

The Elevation Run/Walk is an annual event held in Conifer, Colorado, featuring race distances of 10 miles, 5 miles, and 2 miles. Set at an average elevation of 8,200 feet, the course showcases the scenic Aspen Park neighborhoods, combining paved roads, dirt roads, and trail running. The event suppor..

The Summit 200 is a challenging 200-mile mountain ultramarathon held in Summit County, Colorado. The race features a single 200-mile loop that traverses stunning hiking trails, recreation paths, forest roads, and some pavement, with elevations ranging from over 9,000 feet to nearly 13,000 feet. Part..

The Boulder Rez Marathon, held at Boulder Reservoir in Boulder, Colorado, offers a scenic and mostly flat course with only 200 feet of elevation gain. Runners enjoy trails and dirt roads alongside the reservoir, with stunning views of the water and the Rocky Mountains. The event features multiple di..

The Lory Summer Trail Series is a fun, low-key trail running event held each Tuesday evening in August at Lory State Park, Fort Collins, Colorado. It features a series of shorter races with distances ranging from 5K to 12K, designed to welcome new trail runners and help experienced racers sharpen th..

The Eltuck Valley 5K is part of a series of midweek trail races held at Lory State Park in Bellvue, Colorado. Scheduled for August 5, 2025, this event is designed to cater to both novice and experienced runners, offering a flat and fast course ideal for those looking to improve their speed. Particip..

The Holy COW Trail Stampede is an exciting running event held in Westminster, Colorado, featuring a 10-mile race and 5K/10K options. Participants can enjoy a fun and festive atmosphere while supporting the charity partner, Growing Home, which focuses on breaking the cycle of poverty for families in..

The Run The Rockies Trail Race in Frisco, Colorado, offers 5k, 10k, and half marathon distances along scenic trails on the Frisco Peninsula. The course features single track and dirt road trails with stunning views of Dillon Reservoir and the Ten Mile Range. Starting and finishing at the Frisco Nord..

Dirt Circus - Boulder is a free community running event held in Boulder, Colorado, celebrating local trail running culture. Organized by UltraSignup, this one-day festival features a social group run with options of a casual 4.5-mile or 10K route through local trails. The event fosters camaraderie a..