Ultramarathons in Colorado
Discover ultramarathon and trail running races across Colorado. Browse upcoming events, view course maps, and explore race results.
Mace's Hideout 100
The Mace's Hideout 100 takes place in early June in Colorado's Wet Mountains near Beulah, with runners navigating a challenging course that offers views of the nearby Sangre de Cristo range. This is a demanding 100-mile effort with a 36-hour cutoff, featuring a mix of out-and-backs sections across the loop that bring you through the same aid stations twice—a format that can be mentally tough as you retrace familiar ground while fatigue builds. The course moves through varied mountain terrain, transitioning between forested sections and more exposed areas with climbing spread throughout. Fourteen aid stations provide regular support, with pacers allowed starting at mile 46 and drop bag access at key points. June conditions in this part of Colorado can bring afternoon thunderstorms and significant temperature swings from morning starts to midday heat, so weather preparedness matters. Runners who handle technical mountain terrain well and don't mind the mental challenge of repeated sections will find this race suits them. The aid station layout means you'll see other runners regularly, which some find motivating and others find distracting. Those looking for a straightforward point-to-point mountain experience might prefer different formats, but runners who appreciate the logistics and familiar checkpoints of this style will likely enjoy the challenge.
24 Hours of Palmer Lake
The 24 Hours of Palmer Lake is a timed ultramarathon where runners complete as many laps as possible on a short 0.82-mile loop course over 24 hours, from 8 AM Saturday to 8 AM Sunday. Set at 7,240 feet elevation on Colorado's Palmer Divide, the course offers mountain views but little variation in terrain or scenery as you circle the same route dozens of times. The format strips away most trail running variables—no navigation, minimal elevation change per loop, and constant access to crew support and aid at the single station. What remains is a pure test of endurance and mental fortitude as you rack up miles in short increments. The high altitude adds a cardiovascular challenge, especially for runners not accustomed to elevation, while the repetitive nature can be either meditative or maddening depending on your mindset. This race appeals to runners looking to test distance limits without technical terrain, those training for longer events, or anyone curious about the mental game of loop running. If you need varied scenery or challenging terrain to stay engaged, the repetitive nature might feel tedious. Runners comfortable with their own thoughts and motivated by accumulating miles will find this format oddly compelling.