Boulder Sunset 5K/10K

Boulder Reservoir 5565 N 51st St, Boulder, CO, United States

The Boulder Sunset 10K & 5K Run is part of BBSC’s biggest endurance event of the summer. Spend your weekend racing with BBSC at the incredible and scenic Boulder Reservoir. Register, and start training for the end-of-the-summer endurance festival with BBSC.

Event Series Endurance Race Series

Westminster Trail Race

Wayne Carle Middle School 10020 100th Ave, Westminster, CO, United States

Join us at beautiful Standley Lake in Westminster for an unforgettable evening at the Westminster Night Trail! For its 12th year, this race takes on a whole new energy as runners hit the scenic trails of Standley Lake under the stars. With a mix of packed dirt trails, single-track, and a hint of bike path, this […]

Grand Traverse Mountain Run

Mt. Crested Butte Mt. Crested Butte Ski Resort, Crested Butte, CO, United States

The Grand Traverse Mountain Run is a point-to-point ultra marathon from Crested Butte to Aspen, Colorado. The course follows the route of the Grand Traverse Backcountry Ski race. In total, runners travel 40 miles across the Elk Mountains with over 6,000′ of elevation gain.

Snow Mountain Ranch Trail Festival

YMCA of the Rockies - Snow Mountain Ranch 1101 County Rd #53, Granby, CO, United States

Join us at the YMCA of the Rockies in Granby for the 12th annual Snow Mountain Ranch Trail Running Festival. This event features 4 races with 2 different "challenges".  Races will include a Half Marathon,10K, 5K, and 50K. Challenge yourself with our popular "Moosehead Challenge" and "Baby Moose Challenge" by completing multiple events in a single day. […]

Bear Chase Trail Race

Bear Creek Lake Park 15600 W Morrison Rd, Lakewood, CO, United States

The Bear Chase Race Endurance Festival is a 100K, 50 Mile, 50K, Half Marathon and the Baby Bear 10K trail race at beautiful Bear Creek Lake Park, in Lakewood, CO. Ultra races on Saturday, short trail races on Sunday An excellent race for first time trail and ultramarathoners, runners will experience a variety of challenging […]

Event Series PPRR Nielson Challenge

PPRR Nielson Challenge

North Monument Valley Park 1794 Culebra Ave., Colorado Springs, CO, United States

Race Format The first time you run this event, you'll establish a base time for yourself. This base time is used to generate a handicap time. The handicap time is calculated using an algorithm developed by Bob Royse, and it's geared to favor a beginning runner and the slower runners. Click here for an explanation of the […]

Event Series PPRR Nielson Challenge

PPRR Nielson Challenge

North Monument Valley Park 1794 Culebra Ave., Colorado Springs, CO, United States

Race Format The first time you run this event, you'll establish a base time for yourself. This base time is used to generate a handicap time. The handicap time is calculated using an algorithm developed by Bob Royse, and it's geared to favor a beginning runner and the slower runners. Click here for an explanation of the […]

Louisville Trail Race

Louisville Community Park 955 Bella Vista Dr, Louisville, CO, United States

The 12th Annual Louisville Trail Half Marathon, 10K, and 5K returns to the front range, beloved by runners for its scenic trails and welcoming atmosphere. The course is mostly flat with a beautiful, yet challenging hill that creates an epic vista point of the front range mountains as you hit the last mile of the […]

Please click here to submit your event for FREE to our online calendar.
We do not allow events without physical locations (IE – virtual runs, runs with locations TBD, etc…).
Please allow 48 hours after submission for an event to appear on the calendar. If you have already listed your event and would like us to update it, please contact us.