Niwot's Challenge

Sedalia, United States • 2-9 May 2026

Niwot's Challenge is a highly demanding ultramarathon held annually in Sedalia, Colorado, along the South Platte River in the Front Range. Modeled after the grueling Barkley Marathons, it features a mostly off-trail course requiring advanced navigation skills using map and compass, with no GPS allowed. The event offers three levels of completion: the Burn Loop (~24 miles, +10,000′ elevation), the Chief's Loop (~50 miles, +20,400′ elevation), and the Deity status (~100 miles, double loops in reverse order). Aid is very limited, and participants must be self-sufficient. The race fosters a close-knit community with secretive course details and a strong emphasis on safety and preparedness. Visit the organization's website for the most recent information.

Race information

100 mi
40800 m+
Deity Status (double Loops)
50 mi
20400 m+
Chief's Loop
24 mi
10000 m+
Burn Loop
Visit the organization's website for the most recent information.
Trail runs nearby

Chase the Moon is a unique 12-hour endurance running event held in Highlands Ranch, Colorado, within the scenic Highlands Ranch Backcountry trail system. Participants can compete solo or as part of 3-person or 5-person relay teams, running loops of approximately 10.3 miles on mostly dirt trails with..

The Elevation Run/Walk is an annual event held in Conifer, Colorado, featuring race distances of 10 miles, 5 miles, and 2 miles. Set at an average elevation of 8,200 feet, the course showcases the scenic Aspen Park neighborhoods, combining paved roads, dirt roads, and trail running. The event suppor..

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 Staunton Rocks! Marathon & Half is a trail running event held at Staunton State Park in Pine, Colorado, in the Front Range Mountains southwest of Denver. The race offers two distances: a marathon (26.3 miles with 4,500 feet of elevation gain) and a half marathon (13.1 miles with 2,200 feet of ga..

The Westminster Night Trail, held in Westminster, Colorado, is a vibrant night trail running event set around scenic Standley Lake. Celebrating its 12th year, the race offers multiple distances: 50K, 35K, half marathon, 10K, and 5K, all on 100% packed dirt trails featuring a mix of single-track and..

The Rock Hawk Trail Races take place at Philip S. Miller Park in Castle Rock, Colorado, featuring distances of 50K, 25K, 10K, and 5K. The event is set on the scenic, rolling trails of Miller Park and the Ridgeline Trail systems, offering a course that is not overly technical but still challenging an..