Trail Running calendar near Boulder 2025-2026

The Big Brrrrito event offers participants the choice of running 5 miles, 10 miles, or 15 miles through the scenic trails of Chatfield State Park in Colorado. Organized by the Roxborough Running Club, this running event is set to take place on January 25, 2025. Registration for the event will close ..

The Running Up for Air - Staunton Rocks is an endurance running event taking place at Staunton State Park in Pine, Colorado, on February 14-15, 2025. Participants can choose from various challenges, including 3, 6, 12, and 24-hour races, running a marked 7.1-mile loop with significant elevation gain..

The Winter's End Snowshoe Races, hosted by the Human Potential Running Series, is an exciting winter running event taking place at Granby Ranch Resort in Granby, Colorado. Scheduled for March 8, 2025, the event features multiple race distances, including a 2-mile "Fun Run," an 8-mile, a 16-mile, and..

Lucky Lyons is a festive running event held in Lyons, Colorado, featuring 5K and 10K races to kick off St. Patrick's Day celebrations. Participants are encouraged to wear their best green attire as they navigate scenic courses that include paved, gravel, and dirt paths.The event supports the Lyons C..

Run The Ranch is an exciting trail running event held at Sylvan Dale Guest Ranch in Loveland, Colorado. Scheduled for April 4-5, 2025, participants can choose from various distances, including a 5K, 10K, and multiple timed trail runs ranging from 4 to 12 hours, both solo and in relay formats. The ev..

The Great Western Trail Race, taking place in Severance, Colorado, celebrates the region's newest trail connecting Windsor, Severance, and Eaton. Participants can choose from various events, including a 5k, 10k, half marathon, and a Kids Fun Run. The race features a mostly flat and fast course with ..

The Rock Hawk Trail Races, part of the Bear Chase Race Series, take place on April 19, 2025, at Phillip S. Miller Park in Castle Rock, Colorado. This event features multiple race distances, including 50K, 25K, 10K, and 5K, catering to both novice and experienced trail runners.The scenic trails offer..

The Greenland Trail Races, held annually in May at the Greenland Open Space in Larkspur, Colorado, features four race distances: 4 miles, 8 miles, 25K, and 50K. This event is known for its scenic trails with views of Pikes Peak, making it a favorite among runners. Participants enjoy amenities such a..

The Mountain Ridge Trail Race, taking place on May 10, 2025, in Highlands Ranch, Colorado, offers a variety of distance options for trail running enthusiasts, including a 21-mile, half marathon, 10K, and 5K. The event features scenic dirt and single-track trails that showcase the stunning landscapes..

Niwot's Challenge is a challenging ultramarathon held annually in Colorado's Front Range, designed for experienced runners. Modeled after the Barkley Marathons, this grassroots event features a secretive course that requires participants to navigate primarily off-trail using a map and compass. With ..

The Quad Rock 50 and 25 Mile Trail Races, organized by Gnar Runners, will take place on May 10, 2025, in Lory State Park and Horsetooth Mountain Park, near Fort Collins, Colorado. This challenging event features two distances: a 50-mile race with over 11,000 feet of elevation gain and a 25-mile race..

Samson's Revenge is a trail running event held at the YMCA of the Rockies in Estes Park, Colorado, honoring the legacy of Samson, a famous elk poached in 1995. The race features three distances: 10K, 27K, and 55K, with a challenging course that includes a significant ascent known as the King of the ..

The Endure Trail Runs, organized by the Human Potential Running Series, takes place at Mueller State Park in Divide, Colorado. This unique event features a variety of races, including a 10k, Half Marathon, and timed challenges of 12 and 24 hours. Participants in the 12-Hour and 24-Hour events will d..

The Weld Your Mettle Running Festival is a four-day event taking place in Eaton, Colorado, featuring a variety of running challenges suitable for all participants. Events include solo and relay formats ranging from 3 to 24 hours, as well as a 7K run and ruck. The festival offers a vibrant atmosphere..

The Ol' College Try 24 Hour Ultra is Denver's inaugural 24-hour ultra race, organized by Rise Again Running Events in collaboration with Tall Tales Ranch. Scheduled for May 24-25, 2025, at Auraria Campus, this event invites runners of all abilities to challenge themselves and achieve personal bests ..

The North Fork 50 Mile/50K is an ultramarathon set in the picturesque Colorado mountains, just southwest of Denver. This event features a challenging course that is entirely on soft surfaces, primarily consisting of singletrack trails, with some sections of double track. Runners will experience dive..

The Crazy Legs 10k+ Trail Run is set to take place at Devil’s Backbone Open Space in Loveland, Colorado, on June 1, 2025. This event features a challenging trail course marked by flour arrows, with a water stop available for participants. Runners will receive a unique hat and will be timed using a t..

The Great Divide Ultra is a premier trail running event held in Divide, Colorado, featuring a variety of distances including 100 miles, 100k, 50k, and 25k. Set against the stunning backdrop of Mueller State Park, participants can enjoy smooth single and double-track trails amidst picturesque meadows..

The Summits Trail Runs, part of the Human Potential Running Series, is an exciting trail running event set in the stunning Rocky Mountains at Granby Ranch Resort, Colorado. Scheduled for June 14, 2025, the event features multiple race distances, including a challenging 43-mile Quad, a 27-mile Triple..

The Barr Lake Trail Race, taking place in Brighton, Colorado, is a celebrated running event now in its sixth year. It features one of Colorado's flattest and fastest courses, with minimal elevation gain, making it ideal for both seasoned runners and newcomers. Participants can choose from various di..