Trail Running calendar near Boulder 2025-2026

The Weld Your Mettle Running Festival is a four-day event taking place in Eaton, Colorado, from May 23 to May 26, 2025. It offers a variety of running challenges suitable for all levels, including a 7K run, ruck, and timed events ranging from 3 to 48 hours, either solo or as part of a relay team. Pa..

The Ol' College Try 24 Hour Ultra is Denver's first 24-hour ultra race, held at the Auraria Campus in downtown Denver, Colorado. Hosted by Rise Again Running Events in partnership with Tall Tales Ranch, the event offers individual races of 6, 12, and 24 hours, as well as relay options for teams. Par..

The 3rd Latino Ultra Nature Adventure (LUNA) is a unique trail running event scheduled for May 31, 2025, in Boulder, Colorado. This culturally relevant and inclusive event features various distances, including 5km, 7 miles, 15 miles, and a marathon. LUNA aims to promote physical and mental health th..

The Leadville Turquoise Lake 20K is a scenic mountain race held in Leadville, Colorado, featuring a 20-kilometer course around Turquoise Lake. The route begins with 6.5 miles of hilly paved road, followed by 5.5 miles of single-track dirt trail, offering runners stunning views of the surrounding mou..

The Luna (Latino Ultra Nature Adventure) is an inclusive, culturally relevant ultra running event held in Boulder, Colorado. Now in its third year, it offers various race distances, including 5km, 7 miles, 15 miles, and a marathon, all taking place on May 31, 2025. The event emphasizes human-nature..

The Reuter-Hess Trail Incline is a challenging 10k trail race held in Parker, Colorado, featuring about 600 feet of elevation gain. The course begins with a lollipop loop that includes a steep incline with widely spaced stairs, making running difficult. After the incline, runners navigate rolling te..

The North Fork 50 Mile and 50K ultramarathon takes place in the scenic Colorado mountains near Buffalo Creek. The course features nearly all singletrack trails, with some double track sections, traversing diverse landscapes including burn areas from a 1996 fire, ponderosa pines, and granite rock for..

The Fish Hatchery 5K Trail Run takes place at the historic Leadville National Fish Hatchery in Leadville, Colorado. This scenic 5K features a cross-country style course that winds through subalpine forest areas near Evergreen Lakes and lower Rock Creek. The route includes a mix of dirt roads, paths,..

The Crazy Legs 10k+ Trail Run takes place at Devil’s Backbone Open Space in Loveland, Colorado. The course features a scenic loop through Hidden Valley, Hunter Loop, Laughing Horse Loop, and Wild Loop trails, covering over 10 kilometers with minimal overlap to prevent congestion. Marked by flour arr..

The Vail Ultra Benefiting 50 For The Fallen is a 50-mile ultramarathon held in Vail, Colorado, starting at The Hangout at Golden Peak. This challenging mountain race offers participants a scenic and demanding course through the stunning terrain of Vail. The event supports the 50 For The Fallen organ..

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 Great Divide Ultra is a premier trail running festival held in Divide, Colorado, featuring distances of 100 miles, 100K, 50K, and 25K. Set in Mueller State Park, the course showcases stunning spring-fed meadows, massive Pikes Peak granite rocks, and sweeping mountain views. The looped course is..

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..

The Estes Park Backyard Ultra is an endurance running event held along the scenic Lake Estes, supporting Childcare and Family Services. Participants run a 4.252-mile course on a paved bike trail, completing a lap every hour until only one runner remains. The race features no predetermined end time,..

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..

The Leadville Trail Marathon and Heavy Half are challenging trail running events held in Leadville, Colorado, traversing historic mining district trails. The marathon covers 26.4 miles with 6,167 feet of elevation gain, while the Heavy Half is 15.4 miles with 3,421 feet of gain. Both courses reach t..