Aspen Backcountry Marathon

2026

The Aspen Backcountry Marathon takes place in early August on the trails surrounding Aspen, Colorado, starting and finishing at Rio Grande Park. This is a limited-support trail marathon with seven aid stations spread across 26.3 miles and roughly 4,800 feet of climbing, running almost exclusively on dirt trails with an 8.5-hour cutoff. Starting at 7,900 feet elevation, the course climbs through diverse terrain that peaks above 10,000 feet, offering views of the Elk Mountains and the valley below. Runners will encounter everything from forested singletrack to more exposed sections as they navigate the challenging ascents and technical descents that define this high-alpine event. The remote nature of much of the course means aid stations are spaced farther apart than typical road marathons, with some offering only basic supplies like water, electrolytes, and fruit. Weather can be unpredictable at altitude, even in August, so preparation for mountain conditions is essential. This race suits experienced trail runners comfortable with sustained climbing, altitude, and self-sufficiency between aid stations. Runners seeking a fast time or those new to high-altitude trail running may find the combination of elevation gain and thin air more challenging than anticipated. The mountain terrain and limited support structure make this better suited for those with solid trail experience rather than road marathoners looking to try something different.