Trail Running calendar near Boulder 2024-2025

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 is an exciting winter running event scheduled for March 8, 2025, at Granby Ranch Resort in Granby, Colorado. This event welcomes participants of all skill levels, offering a unique opportunity to experience the stunning snow-covered landscape while staying active. Run..

Lucky Lyons is a St. Patrick’s Day running event featuring 5K and 10K races set in the scenic paths of Lyons, Colorado. Scheduled for March 8, 2025, participants are encouraged to wear their best green attire to celebrate the occasion.The courses include a mix of paved, gravel, and dirt paths, provi..

Run The Ranch is an exciting trail running event taking place 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, with options for solo and rela..

The Rock Hawk Trail Races, part of the Bear Chase Race Series, take place 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 a thrilling experi..

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 popular choice for both competitive and recreational runner..

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

The Mountain Ridge Trail Race, taking place on May 10, 2025, in Highlands Ranch, Colorado, offers a variety of distances for trail running enthusiasts, including a 21-mile, half marathon, 10K, and 5K. Celebrating its 11th year, the race features scenic dirt and single-track trails with manageable el..

The Quad Rock 50 and 25 mile trail races, organized by Gnar Runners, will take place in Lory State Park and Horsetooth Mountain Park near Fort Collins, Colorado. This event offers participants a challenging course with stunning views of the Rocky Mountains and the Great Plains. The 50-mile race feat..

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. Participants can choose from three race distances: 10K, 27K, and 55K, featuring a challenging course with significant elevation gain, partic..

The Endure Trail Runs, hosted by the Human Potential Running Series, takes place at Mueller State Park and features a variety of events including a 10k, Half Marathon, 12-Hour, and 24-Hour races. The unique 12-Hour event allows participants to choose their loops based on colored balls drawn from a b..

The Weld Your Mettle Running Festival is a vibrant event taking place over a weekend in May 2025 in Eaton, Colorado. It features a variety of running challenges, including timed relays (3, 6, 9, 12, and 24 hours), a 7K Ruck, and a 1 Mile Kids Fun Run. Participants can enjoy camping options, includin..

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 an exciting running event taking place at Devil’s Backbone Open Space in Loveland, Colorado. Scheduled for June 1, 2025, this trail run features a challenging course marked by flour arrows, with water stops provided along the way. Participants can enjoy a unique expe..

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, hosted at Granby Ranch Resort in Colorado, is an exciting trail running event featuring various distances, including ultra options. Participants can choose from the Quad (43 miles), Triple (27 miles), Double (21 miles), and Single (6 miles) runs, all set against the stunning ..

The Barr Lake Trail Race, taking place in Brighton, Colorado, is a celebrated running event now in its sixth year. It features a variety of race distances including 50K, 30K, half marathon, 15K, and 5K, all set on one of Colorado's flattest and fastest courses with minimal elevation gain. Runners wi..

Estes Park's Backyard Ultra is a unique ultra-running event set against the stunning backdrop of Lake Estes, Colorado. Participants must complete a 4.252-mile loop every hour until only one runner remains, who is declared the winner. This format emphasizes endurance and strategy, as there is no pred..

The Timberview Trail Run is an exciting annual event held at Lory State Park in Colorado, featuring three race distances: a 10-mile, a 5-mile, and a 5K trail run. Scheduled for June 28, 2025, this event welcomes participants of all ages and skill levels, making it ideal for beginners and seasoned ru..