Trail Running calendar near Weld County 2025-2026

The Boulder Rez Marathon, held at Boulder Reservoir in Boulder, Colorado, offers a scenic and mostly flat course with only 200 feet of elevation gain. Runners enjoy trails and dirt roads alongside the reservoir, with stunning views of the water and the Rocky Mountains. The event features multiple di..

The Lory Summer Trail Series is a fun, low-key trail running event held each Tuesday evening in August at Lory State Park, Fort Collins, Colorado. The series features four races with distances ranging from 5K to 12K, designed to welcome new trail runners and help experienced racers sharpen their spe..

The Eltuck Valley 5K is a trail running event held at Lory State Park in Bellvue, Colorado. Scheduled for August 5, 2025, it is the first race in a four-race midweek summer trail series designed for both new and experienced trail runners. The 5K course is noted for being the fastest and flattest of..

The Holy COW Trail Stampede is a trail running event held in Westminster, Colorado, featuring distances including a 5K and a 10-mile race. Participants enjoy a fun, community-focused atmosphere with a western theme, running through scenic trails near the Westminster Promenade Terrace. All runners re..

Dirt Circus - Boulder is a free community running event held in Boulder, Colorado, celebrating local trail running culture. Organized by UltraSignup, the event features a social group run with options of a casual 4.5-mile or 10K route through the local trails. Beyond running, the festival offers foo..

The Into the Hills Eltuck 10K is a challenging trail race held at Lory State Park in Bellvue, Colorado. Part of a four-race summer trail series, this event features the hilliest course with a 1,700-foot elevation gain, offering runners stunning mountain scenery. Designed for both new and experienced..

The Into the Hills Eltuck 5K is a midweek trail race held at Lory State Park, Bellvue, Colorado. Part of a four-race summer series, this event features a challenging course with a steep, quick climb and descent along the Homestead, Well Gulch, and Kimmons loop, offering about 700 feet of elevation g..

The NoCo Urban Ultra & Relay is a long-distance running event held along the scenic Poudre River Trail in Northern Colorado, passing through Fort Collins, Timnath, Windsor, and Greeley. The race offers 50-mile and 100-mile distances for both solo runners and relay teams, with the 100-mile race stage..

The Westminster Night Trail is an annual night trail running event held at Standley Lake in Westminster, Colorado. Celebrating its 12th year, it offers a festive atmosphere with music, lights, and vibrant trail running vibes under the stars. The course features 100% packed dirt trails, including sin..

The Antelope Dash is a trail running event held at Curt Gowdy State Park near Cheyenne, Wyoming. It features 4-mile and 8-mile races that traverse rolling hills and winding trails through a scenic landscape of aspens, pines, reservoirs, streams, granite rock formations, and hoodoos. The course start..

The Bluffs 8K Trail Run is a challenging race held at Bluffs Regional Park in Lone Tree, Colorado. The course features rolling hills and beautiful views, with a mix of fine crushed gravel and some rugged, steep sections. The race starts and finishes near the Prairie Sky Park parking lot.Participants..

The Eltuck Valley 12K is part of the Lory Summer Trail Series held at Lory State Park in Bellvue, Colorado. This midweek trail race series offers distances ranging from 5K to 12K, catering to both new and experienced trail runners. The August 26 race features a fast and flat 12K course along the Val..

Front Range Ultra Dayze is an ultra-running festival held in Loveland, Colorado, featuring a variety of ultra-distance events including 50k, 100-mile, 200-mile, and timed races from 12 to 100 hours. The course is a flat, fast 2-mile loop with 80% dirt trail and 20% pavement, set in Centennial Park a..

The Calarat Challenge Trail Running Festival takes place in Jamestown, Colorado, at the scenic Cal-Wood Education Center and Balarat Outdoor Education Center. Held over Labor Day weekend, the event features multiple trail races including a half marathon, 10K, 5K, Kids 1K, and combination races like..

The American Heroes Run, held in Longmont, Colorado, is a patriotic running event commemorating the events of 9/11. It features a variety of distances including a 100-mile ultra with a 30-hour cutoff, a 24-hour run, marathon, half-marathon, 9.11-mile, and 5K races. The course is a flat, fast 1.05-mi..

The HRCA Wildcat Mountain Trail Races take place in Littleton, Colorado, starting at the Douglas County East/West trailhead near Rocky Heights Middle School. The event features 10K and 10-mile trail races along the scenic HRCA Backcountry Wilderness Area Wildcat Mountain trail system, offering 100%..

The Black Squirrel Half Marathon is a challenging 13.5-mile trail race held in Lory State Park near Fort Collins, Colorado. Featuring approximately 2,000 feet of elevation gain and loss, the course offers a scenic perimeter tour of the park with stunning views of Horsetooth Reservoir, Fort Collins,..

The Ned Ned Half Marathon is a long-standing trail running event held in Nederland, Colorado, celebrating 43 years of tradition. Set in the picturesque mountain town of Nederland at 8,236 feet elevation, the race offers a challenging 13.3-mile course with 1,408 feet of elevation gain, featuring dirt..

The Red Feather Trail Jamboree is a three-day trail running event held at Ben Delatour Scout Ranch in Red Feather Lakes, Colorado. Scheduled for September 26-28, 2025, it offers three race distances: a 50-mile ultra with 8,500 feet of elevation gain, a 50K with 4,200 feet gain, and a half marathon f..

The Bear Chase is a trail running endurance festival held at Bear Creek Lake Park in Lakewood, Colorado. It offers multiple race distances including 100K, 50 Mile, 50K, Half Marathon, 10K, and 5K, catering to both first-time ultramarathoners and experienced trail runners. The course features mostly..