Trail Running Calendar Colorado 2025-2026

The Summit 200 is a 200 mile loop from Frisco, Colorado, over high alpine trails and forest roads with nearly 40,000 feet of ascent. Limited to 100 runners and with remote aid, this epic self reliant race has a 110 hour cutoff.

Join the Wild West Relay, a scenic point to point 200 miles across Colorado from Fort Collins to Steamboat Springs. Run solo or with teams from 1 up to 12 people as you tackle mountain passes, open roads and big western views.

Tackle high alpine trails at Sheep Mountain Trail Runs in Fairplay, Colorado on August 1, 2026, with options for a half marathon, 50k, or 50 mile. Expect rocky county and forest roads, aid stations, big views, and a supportive festival vibe..

Tackle a scenic 15 mile high altitude trail to Kennebec Pass with sweeping river valley views and alpine wildflowers. Limited to 150 runners and benefiting La Plata County Search and Rescue, this intimate mountain run rewards effort with ho..

Run the Aspen Backcountry on August 1, 2026, a rugged trail race from Rio Grande Park that climbs into high alpine terrain. Choose from marathon, 50K or heavy half courses and enjoy scenic singletrack, remote aid and festival vibes.

Run the Lory Summer Trail Series in August at Lory State Park: four midweek trail races from 5K to 12K with scenic climbs and friendly competition. Stay after each race for pizza, drinks and a free vintage shirt, plus series awards.

Run the Lory Summer Trail Series in August at Lory State Park: four midweek trail races from 5K to 12K with scenic climbs and friendly competition. Stay after each race for pizza, drinks and a free vintage shirt, plus series awards.

High Five 100 is a self guided mountain challenge from Lake City, Colorado: roughly 90 to 105 miles with about 40,000 ft of climbing and summiting five 14ers. Finish the unmarked route within 48 hours; registration opens January 1, 2026.

Run the Rockies Trail in Frisco, Colorado offers 5k, 10k and half marathon on scenic single track and dirt trails. Take in views of Dillon Reservoir and the Ten Mile Range with a lakeshore finish to cheer your arrival.

The Emerald Mountain Epic is a two day trail festival in Steamboat Springs blending mountain biking and trail running on rugged singletrack with big elevation gains. Enjoy fully stocked aid, a lively finish area, and proceeds that benefit l..

Take on the iconic Leadville Trail 100 Run, a 100 mile ultramarathon through the Colorado Rockies that climbs to Hope Pass and delivers breathtaking high altitude views. A true test of endurance and grit.

Experience scenic high altitude trail running in Fraser, Colorado at the Byers Peak Stampede Half Marathon and 5K, a fundraiser for the Shining Stars Foundation. Tackle a challenging half above 9,500 ft or enjoy a dirt road 5K.

Staunton Rocks! Marathon and Half deliver high altitude singletrack through Staunton State Park, offering sweeping mountain views, alpine wildlife, and serious vertical gain. With just 150 spots per distance, this rugged trail run fills fas..

Challenge yourself on the scenic rolling trails of Philip S. Miller Park in Castle Rock at Rock Hawk Trail Races on August 29, 2026, with 50K, 25K, 10K and 5K distances. Organized by Aravaipa Running, the event supports local open spaces an..

Epic point to point ultramarathon from Mt Crested Butte to Aspen across the Elk Mountains. Tackle 40 miles and over 6,000 feet of climbing on high alpine terrain while supporting Crested Butte Nordic.

Challenge yourself on the Cirque Series at Arapahoe Basin on September 5, 2026 in Keystone, Colorado. This scenic 9.4 mile mountain course with 2,211 ft of climbing delivers steep, technical trail and big alpine views in a capped field.

Ned Ned Run in Nederland Colorado blends scenic trail and road running through the foothills, offering a half marathon, 10K and fun 5K for all abilities. Family friendly and costumes encouraged, with leashed dogs welcome in the 5K.

Run alpine trails and rolling hills at Snow Mountain Ranch Trail Running Festival in Granby CO on September 12, 2026. Choose 50K, 33K, half marathon, 10K or 5K and enjoy sweeping mountain views and friendly aid stations.

Experience the Black Squirrel Half Marathon at Lory State Park near Fort Collins on September 12, 2026. This 13.5 mile trail course features rolling singletrack with sweeping reservoir and mountain views and a pint glass plus pancake breakf..

Run Rabbit Run is a Steamboat Springs, Colorado trail ultramarathon on Sept 18 and 19, 2026 offering 50 mile and 100 mile courses with major alpine climbs. The race raises funds for northern Colorado charities.