Trail Running calendar near Nederland 2026-2027

A multi-distance race at Boulder Reservoir, Colorado, featuring a mostly dirt and trail course with about 200 feet of elevation gain and views of the reservoir and the Rocky Mountains.

Trail ultras from Roxborough State Park to Sharptail Trailhead featuring sustained climbs, technical singletrack, and a long runnable finish, with full aid support and an emphasis on land stewardship.

Westminster Trail Race at Standley Lake in Westminster, Colorado offers five dirt-trail distances from 5K to 50K with lake and Front Range views on out-and-back and Y routes.

Summit Grays and Torreys Peaks in this 8.8 mile Colorado endurance event. Participants must carry a 20lb dry load while tackling 4,101 feet of elevation gain.

A 10 km out and back in Leadville on August 16, 2026 that uses the opening and closing sections of the LT100 Run course. Aid at the turnaround and liquids on the Courthouse lawn, minimum age 12, general registration open.

Experience a hilly 5k trail race through the scenic Lory State Park. Enjoy a low key atmosphere followed by pizza, beverages, and a vintage race shirt in this midweek summer series event.

A four‑race midweek trail series at Lory State Park in August 2026 offering 5k, 10k and 12k courses with varied elevation. Series and per-race registration, post-race food and drinks, and end-of-series awards for top points scorers.

A 60 hour endurance challenge at Snow Mountain Ranch where runners repeat a 10 mile trail loop to reach milestone distances. Entry includes lodging, meals, training and recovery services.

A high-elevation, approximately 100-mile out-and-back ultramarathon in Leadville, Colorado, featuring Hope Pass and over 15,000 feet of climbing. The event uses an entry lottery and includes 11 aid stations, pacer allowance, and buckle awar..

Experience a high altitude trail run through the Rocky Mountains on 100 percent unpaved roads and trails. This dog friendly event in Fraser supports children facing cancer through the Shining Stars Foundation.

Experience high altitude trail running through the scenic singletrack and historic landmarks of Staunton State Park. Choose between a full or half marathon featuring sweeping mountain views and a festive post-race meal.

Trail races in Arrowhead, Colorado on August 22, 2026 include a 13.3 mile half marathon with 2,844 ft of climbing and a mostly downhill 5.6K. Courses run mostly on single track and finish at Arrowhead Village with awards and post race food.

Experience a fast and flat 12k trail race through the scenic Valley Trails of Lory State Park. Enjoy a low key atmosphere followed by pizza, beverages, and a vintage race shirt in Bellvue.

Rock Hawk Trail Races in Philip S. Miller Park, Castle Rock, CO offers 50K, 25K, 10K and 5K on rolling ridgeline trails with cup free aid stations, live split tracking, and official chip timing.

A mountain trail race in Steamboat Springs with 50K, 16 mile, and 5 mile options, high-elevation climbs, cupless aid stations, and limited crew access to one aid station. Leashed dogs are allowed on the 5 mile course only.

A community trail event at the Arapahoe County Fairgrounds on 08/29/2026 with a 5K run, a family 5K walk that allows leashed dogs, and a kids 1 mile plus demonstrations, vendors, and a pancake breakfast.

Run Like the Wind in Allenspark on August 29, 2026 features a 5K race, a 2K run/walk and a dog jog option. Proceeds benefit The Old Gallery and participating dogs are entered in an amateur dog show.

A multi-day ultrarunning event in Loveland Colorado with multiple timed and distance races on a 2 mile loop. Camping is allowed in a designated park area and a 24/7 aid station supports runners throughout the event.

A 9.4-mile, 2,211 ft mountain trail race at Arapahoe Basin on September 5, 2026, capped at 700 runners. The course climbs from Mountain Goat Plaza to Little Lenawee summit and returns via alpine and singletrack trails, finishing with music..

Join the community for a 5K run or walk on a brand new dirt course at the North Arvada Middle School Athletic Complex. Support local high school racers before taking on this off road route yourself.