Trail Running Calendar Colorado 2025-2026

Run high alpine trails around Aspen with big climbs and stunning views in a 50K, marathon, or heavy half. Starts and finishes at Rio Grande Park on August 1 and shares the day with Duck Derby festivities, live music, and food trucks.

Run the Lory Summer Trail Series at Lory State Park in Fort Collins this August with four midweek trail races from a fast 5k to a testing 12k. Perfect for newcomers and speed seekers, with post race pizza, drinks, and 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.

Two days of singletrack adventure in Steamboat Springs featuring mountain bike and trail runs through meadows and aspen with big climbs. Proceeds benefit local nonprofits and racers get aid stations and a lively finish.

The Leadville Trail 100 Run is a legendary 100 mile ultramarathon in the Colorado Rockies that tests runners at high altitude with climbs to Hope Pass and sweeping mountain trails. Iconic belt buckles await finishers who make the 25 or 30 h..

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.

Tackle scenic rolling trails at Philip S. Miller Park in Castle Rock with 5K, 10K, 25K or 50K options to suit every runner. Enjoy runnable singletrack, cup free aid stations, and a real challenge on the longer distances.

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.

High alpine trail festival at YMCA of the Rockies in Granby, CO offering 5K to 50K races, plus Moosehead and Baby Moose challenge options. Expect dirt singletrack, big climbs and sweeping mountain views for all abilities.

Run Rabbit Run in Steamboat Springs Colorado is a rugged trail ultramarathon with 50 mile and 100 mile options that climb high alpine terrain. Limited fields, major prize money and charity support draw elite and adventurous runners.

Enjoy a challenging 13 mile trail run in breathtaking Ouray, Colorado, starting and finishing at Fellin Park. This community fundraiser supports the Ouray School and helps fund student trips, with free entry for local students and staff.

Race to the summit of Pikes Peak on the historic Barr Trail in Manitou Springs, Colorado. Choose the full marathon up and down the 14,115 foot peak or the uphill Ascent for an epic alpine challenge and unforgettable views.

Race to the summit of Pikes Peak on the historic Barr Trail in Manitou Springs, Colorado. Choose the full marathon up and down the 14,115 foot peak or the uphill Ascent for an epic alpine challenge and unforgettable views.

Experience the Red Feather Trail Jamboree at Ben Delatour Scout Ranch with 50 mile, 50K and half marathon options across high elevation singletrack and technical mountain trails. Expect big views, wildlife and well stocked aid stations.

Experience the Sangre de Cristo Trail Festival near Westcliffe, Colorado in late September, featuring trail races from 8 miles to 100 miles on the Rainbow Trail. Camping on site and finisher awards add festival atmosphere while 100 mile fin..

Crested Butte Ultra offers high alpine single track racing in Colorado with 50 Mile, 55K and 35K options through Gunnison National Forest. Expect sweeping mountain ridge views, cupless aid stations, custom swag and a finisher buckle.

Run rolling single track and forest roads around Buena Vista, Colorado, with sweeping Collegiate Peaks views. Choose a 30K or 50K and soak up 14er Fest vibes with camping, live music and local vendors.