Trail Running Calendar Colorado 2026-2027

A single 200 mile loop around Summit County Colorado across high mountain trails and forest roads, with about 40,000 feet of elevation change, live GPS tracking, 12 aid stations and a small capped field of runners.

STRS #4 - Tom's Baby on July 29, 2026 takes place at Tom's Baby Trailhead in Breckenridge, CO, offering short and long course entries with adult, youth, and non-binary categories and published entry fees.

An overnight team relay covering 200 miles and 36 legs from Fort Collins to Steamboat Springs, crossing two mountain passes. Multiple team categories are offered and teams choose between supplying volunteers or donating to Windsor Gives.

Experience high elevation trail running in the mountains of Fairplay Colorado. This event offers three distances ranging from a half marathon on forest roads to technical ultramarathons through remote wilderness terrain.

A 15 mile mountain trail run on August 1, 2026 that climbs about 3,100 feet and reaches over 12,000 feet at Kennebec Pass. The course offers alpine terrain and views of the Animas and Dolores River valleys while supporting La Plata County S..

High alpine trail running in Aspen with 50K, marathon and heavy half marathon options and a finish festival at Rio Grande Park.

A mountain trail event in Winter Park, CO offering 50K, 21K, and 10K courses across high alpine singletrack with significant elevation gain, staffed aid stations, age group awards, and town finish at Rendezvous Event Center.

A steep 4.3 mile uphill trail race from Vail Village to Mid Vail with significant elevation gain, on course aid stations, finish food and age group awards.

Two Brothers Up and Down in Idaho Springs offers two uphill out and back races on mixed dirt and paved roads, with steep sections and an aid station on the 10k. Both races start and finish at Courtney Riley Cooper Park.

A pack burro race in Buena Vista Colorado on Aug 2 2026 with 13.1 mile and 7.3 mile courses offered both with and without burros. Burro teams must meet specific equipment and conduct rules and finishers receive a gift and a meal.

A four-race midweek trail series at Lory State Park in August 2026 offering 5k to 12k courses, timed by chip with series points and end of series awards. Pizza and beverages follow each race and vintage shirts are available.

High Five 100 in Lake City CO is a self navigated 100 mile challenge visiting 24 proof points and checkpoints with a 48 hour cutoff. The unmarked route covers roughly 90 to 105 miles and more than 40,000 ft of elevation gain.

A two day running event in Snowmass Village on August 7 and 8, 2026 offering 3.76k, 5k and a single 10k plus an 18.76k challenge. Finishers receive a free New Belgium brew and event medals; proceeds support local nonprofits.

Trail races of 5K, 10K, and half marathon on Frisco Peninsula trails with lakeshore finishes at Dillon Reservoir on August 8, 2026.

Two day mountain bike and trail running event in Steamboat Springs on August 8 and 9 2026. Multiple distances from a 52 mile solo bike to 26.2 and 13.1 mile runs, with proceeds supporting local youth and trail organizations.

The 21st Annual Reece's Roundup is a trail event in Castle Rock featuring a 5K and a 1 Mile Walk, with proceeds supporting a benefit fund that helps a family manage the care needs of a young person with spinal muscular atrophy.

Trail run at Rampart Reservoir with 8 mile and 16 mile options on single track and rocky sections. Entry is limited to 150 and registration closes August 5, 2026.

A traditional pack-burro race in Leadville, Colorado at over 10,000 feet where each team is one runner and one burro carrying mining tools. The long course is about 21 miles and a shorter 6 to 8 mile course is planned.

A hilly 10K trail race at Lory State Park in Bellvue, Colorado, featuring about 1,700 feet of elevation gain, a 100-runner cap, chip timing, and post-race pizza and beverages as part of a midweek series.

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.