Trail Running calendar near Windsor 2025-2026

Niwot's Challenge is a demanding ultramarathon held in Colorado's Front Range, inspired by the Barkley Marathons. This grassroots event, limited to 40 participants, emphasizes navigation skills as runners traverse mostly off-trail terrain using only a map and compass. The challenge includes various..

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 on May 10, 2025, in Lory State Park and Horsetooth Mountain Park, near Fort Collins, Colorado. This challenging event features a scenic course with significant elevation gains—over 5,500 feet for the 25-mile race an..

Samson's Revenge is a trail running event held in Estes Park, Colorado, featuring 55k, 27k, and 10k races. The course is a fast single-track trail with significant elevation gain, including a notable ascent at Bible Point. Runners will start and finish at the YMCA of the Rockies, running on Samson's..

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 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 in a non-stop race, fosteri..

The Pilot Hill 25K is Wyoming's oldest continuously run footrace, originating in the 1970s. This classic race features a challenging course on rugged trails, including sandy flats and steep climbs, culminating at the summit of Pilot Hill, offering stunning views of the surrounding mountains. Partici..

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 Reuter-Hess Trail Incline is a unique running event held in Parker, Colorado, featuring a challenging 10k course and a 1-mile kids' race. The race employs a handicap start system, allowing participants of varying ages and genders to compete on an equal footing. The course includes a steep inclin..

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 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 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 offers participants a challenging course marked by flour arrows, with hydration stations provided along the route. Runners can enjo..

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 various race distances, including a challenging 43-mile Quad, a 27-mile Triple,..

The Barr Lake Trail Race, held in Brighton, Colorado, celebrates its sixth year with a scenic and fast course around Barr Lake. The event offers multiple distances, including a 50K, 30K, half marathon, 15K, and 5K, all on dirt trails with minimal elevation gain, making it ideal for PR seekers and tr..

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 Timberview Trail Run is a scenic trail racing event held at Lory State Park in Colorado, featuring three distances: 5K, 5 miles, and 10 miles. The race offers a beautiful course among treetops with views of Horsetooth Reservoir and the surrounding foothills. The 5K is beginner-friendly, while th..

Chase the Moon is a unique 12-hour endurance run held in the Highlands Ranch Backcountry trail system, offering participants the chance to run solo or as part of a relay team under the full moon. The event features various race options, including solo runs of 12, 6, and 3 hours, as well as a 50K dis..

The Never Summer 100km and 60km races will take place from July 25-27, 2025, in the stunning landscapes of State Forest State Park, Colorado. This challenging mountain race features a variety of terrains, including high alpine ridges, meadows, and rocky trails, with participants experiencing breatht..

The Boulder Rez Marathon is a scenic running event held at the Boulder Reservoir in Colorado, featuring a variety of race distances including a marathon, half marathon, 3/4 marathon, and 10K. The course primarily consists of dirt roads and trails, offering stunning views of the reservoir and the Roc..