Crested Butte Ultra 55K

2026

The Crested Butte Ultra 55K covers roughly 34 miles through Colorado's Gunnison National Forest in late September. This out-and-back style course climbs 4,567 feet from a starting elevation of 8,822 feet up to 11,290 feet, meaning you'll feel the altitude whether you're used to it or not. The route follows singletrack trails through mountain meadows and up to exposed ridgelines, with wide-open views that help distract from the steady climbing. Expect to move between shaded forest sections and more exposed terrain as you work toward the high point. Fall colors should be near peak in late September, though weather can be unpredictable at this elevation and time of year. The course uses a cupless format, so plan to carry your own reusable cup for the five aid stations. Runners comfortable with sustained climbing at altitude will find plenty to enjoy here, while those new to high-elevation racing might find the combination of distance and elevation more challenging than expected. The late-season timing means cooler temperatures but also the possibility of weather shifts, so come prepared for mountain conditions.