Thousands of runners gathered in Denver, Colorado, this weekend for the 20th annual Colfax Marathon [1, 2].
The event serves as a critical hub for the regional athletic community, acting as a Boston Marathon-qualifying race and the largest marathon weekend in the Rocky Mountain region [1, 3].
The festivities took place from Saturday, May 16, through Sunday, May 17, 2026 [2, 1]. The anniversary celebration featured a variety of race lengths to accommodate different skill levels, including a full marathon, a half marathon, a 10-mile race, a 5K, and a relay [3].
Organizers saw a massive turnout for the milestone year. More than 28,000 participants were expected for the event [3], with estimates indicating approximately 28,000 runners actually took to the streets of Denver [1].
The race continues to be a signature event for the city, utilizing the iconic Colfax Avenue to challenge participants with the local terrain. Because the event is a qualifier for the Boston Marathon, it attracts both local enthusiasts and elite athletes seeking to meet strict time standards for the prestigious Massachusetts race [1, 3].
“The largest marathon weekend in the Rocky Mountain region”
The 20th anniversary of the Colfax Marathon underscores Denver's growth as a center for endurance sports in the U.S. By maintaining its status as a Boston Marathon qualifier, the event ensures a steady influx of high-performance athletes, which boosts the local economy and reinforces the city's profile in the national running circuit.
