Trail Running calendar near Centennial 2025-2026

The Sheep Mountain Ultras, part of the Human Potential Running Series, is an annual trail running event held in Fairplay, Colorado. Scheduled for August 2, 2025, it features three race distances: a challenging 50-mile, a 50k, and a half marathon, all set against the stunning backdrop of the South Pa..

The Lory Summer Trail Series, taking place from August 5 to August 26, 2025, offers a series of midweek trail races at Lory State Park in Fort Collins, Colorado. Participants can choose from distances of 5K, 10K, and 12K, designed to cater to both novice and experienced runners. The event aims to cr..

The Eltuck Valley 5K is a part of a fun summer trail race series held at Lory State Park in Bellvue, Colorado. This event is designed for both novice and experienced runners, offering a flat and fast course that serves as the first race in the series. Participants can enjoy a friendly atmosphere, wi..

The Holy COW Trail Stampede is an exciting running event held in Westminster, Colorado, featuring a 10-mile race and 5K/10K options. Participants can enjoy a fun and festive atmosphere while supporting the charity partner, Growing Home, which focuses on breaking the cycle of poverty for families in ..

The Into the Hills Eltuck 10K is part of a fun summer trail race series held at Lory State Park in Bellvue, Colorado. Scheduled for August 12, 2025, this event features a challenging 10K course with a significant elevation gain of 1,700 feet, making it the hilliest race in the series. The series aim..

The Leadville Trail 100 Mile Run, known as the "Race Across the Sky," is a prestigious ultramarathon held annually in Leadville, Colorado. Established in 1983, it challenges participants with a grueling 100-mile out-and-back course that features extreme elevation changes, reaching a peak of 12,600 f..

The Into the Hills Eltuck 5K is part of a series of midweek trail races held at Lory State Park in Bellvue, Colorado. Scheduled for August 19, 2025, this event features a challenging course with a steep climb and descent, making it suitable for both novice and experienced trail runners. Participants..

The NoCo Urban Ultra & Relay is a long-distance running event taking place on August 22-23, 2025, along the scenic Poudre River Trail in Northern Colorado. Participants can choose from a 50-mile solo race, a 100-mile solo race, or relay options for both distances. This inaugural event, organized by ..

The Westminster Night Trail, celebrating its 12th year, invites runners to experience a thrilling night race around Standley Lake in Westminster, CO. This event features various distances, including 50K, 35K, Half Marathon, 10K, and 5K, all set on a mix of packed dirt trails and single-track paths. ..

The Staunton Rocks! Marathon and Half Marathon, scheduled for August 23, 2025, is a premier trail running event held in Staunton State Park, Colorado. Designed by trail runners for trail runners, the event features a challenging yet accessible course that showcases the park's stunning landscapes, in..

The Eltuck Valley 12K is part of the Lory Summer Trail Series, taking place at Lory State Park in Bellvue, Colorado. This event is designed for both novice and experienced trail runners, offering a fun and low-key atmosphere. The series includes four races, with distances ranging from 5K to 12K, all..

The Front Range Ultra Dayze is an exciting ultra-running event taking place in Loveland, Colorado, from August 28 to September 1, 2025. This festival features a variety of ultra-distance races, including 200-mile, 100-mile, and timed events ranging from 12 to 100 hours. Participants can camp for fre..

The American Heroes Run is a commemorative running event held in Longmont, Colorado, designed to honor the heroes of 9/11 and promote patriotism. Participants can choose from various race distances, including a 100-mile run, marathon, half-marathon, 9.11-mile run, and a 5K. The event features a scen..

Devil on the Divide is a challenging trail running event held in Empire, Colorado, featuring two race distances: a 50K and a 22K. Participants will experience breathtaking views of Clear Creek County and the Continental Divide, with the 50K course reaching altitudes over 13,000 feet and climbing mor..

The Cirque Series - Arapahoe Basin is a challenging mountain running event set in Keystone, Colorado, featuring a 9.2-mile course with an elevation gain of 2,411 feet. Participants start at 10,780 feet and navigate through scenic trails, including the High Noon parking lot and Black Mountain Lodge, ..

The HRCA Wildcat Mountain Trail Races, scheduled for September 6, 2025, in Littleton, Colorado, features a variety of events including a 10-mile race, a 10K, and a Kid's Race. The races start at the Douglas County East/West trailhead and traverse the scenic HRCA Backcountry Wilderness Area. Particip..

The Black Squirrel Half Marathon, scheduled for September 6, 2025, takes place in Lory State Park near Fort Collins, Colorado. This challenging 13.5-mile race features approximately 2,000 feet of elevation gain and descent, offering runners stunning views of Horsetooth Reservoir and the Rocky Mounta..

The Snow Mountain Ranch Trail Race, held at the YMCA of the Rockies in Granby, Colorado, is a scenic trail running festival featuring multiple race distances: 50K, 33K, Half Marathon, 10K, and 5K. Set against the stunning backdrop of the Rockies, participants can enjoy rolling hills and vibrant fall..

The Pony Express Trail Run is a scenic trail running event held at Rampart Reservoir, featuring two distance options: 8.5 miles and 16 miles. Set at an elevation of over 9,000 feet, participants can enjoy beautiful single-track trails, creeks, and local wildlife amidst Colorado's autumn scenery. The..

The Pikes Peak Ascent is a challenging running event that takes place in Manitou Springs, Colorado. Covering a distance of 13.32 miles with an elevation gain of 8,000 feet, participants race from Manitou Springs to the summit of Pikes Peak. To ensure safety and preparedness, all runners must complet..