Boulder Rez Marathon

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

The Boulder Rez Marathon is quickly becoming a Boulder classic! This isn’t just another run around the lake. September temperatures will create the perfect race atmosphere. BBSC will offer a […]

Rocky Mountain Tri-Fest

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

Rocky Mountain Tri-Fest is Colorado's newest Multisport event, catering to the whole family. With events for everyone from mom and dad looking to try their hand at a gravel triathlon, […]

Boulder Sunset Triathlon

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

Summer may be coming to an end, but our tri season is still heating up! Join us at the Boulder Reservoir for the 13th Annual Boulder Sunset Triathlon, a local […]

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, […]

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 […]

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, […]

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 […]

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. […]

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 […]

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.