Boulder Rez Marathon

Boulder XC Series Meet 1 is a family-friendly cross-country event held at Valmont City Park (South) in Boulder, Colorado (5110 Valmont Rd). The meet offers three distances: 1K for younger runners, 3K for those up to 16, and a 5K open race,..

Rocky's Backyard Ultra near Estes Park has runners loop 4.167 miles each hour until one remains, with Long's Peak views and 500 feet of climb. Expect variable October mountain weather, aid station, cash and buckle prizes.

Run scenic single track trails near the Denver skyline at the Great Trailhead Foot Race in Bear Creek Lake Park on October 18, 2025. Choose 5 or 10 miles, get a tech tee and post run party, and 10 mile finishers earn a mug.

Tackle scenic dirt trails at Bear Creek Lake Park with 5 km, 15 km, a 5 plus 15 double, or a kids 1 km. Registration includes socks or a neck gaiter and a pancake breakfast while kids earn a stuffed bear at the finish.

The Colleen De Reuck XC Classic is a cross country running event held annually at Harlow Platts Community Park in Boulder, Colorado. Honoring renowned distance runner Colleen De Reuck, the race promotes health, fitness, and celebrates local..

Run the Louisville Trail Race on November 15, 2025, amid the Flat Irons with 13.1, 10K or 5K dirt courses on scenic trails. Enjoy post race festivities and bring a reusable cup or purchase one onsite.