Boulderthon Boulder Marathon

Challenge yourself in Boulder, Colorado, a legendary training hub for elite competitors. Select your distance—5k, 10k, half marathon, or full marathon—and race along routes that wind through the breathtaking Rocky Mountain foothills. Push your limits on the same streets that Olympians use to hone their performance, surrounded by a field of dedicated runners from across the country and around the world.

Consistently ranked among the nation’s top marathons and half marathons, this event is celebrated for its fast, scenic course and attracts thousands of athletes each year. After crossing the finish line, join a lively after-party in downtown Boulder, where you can celebrate endurance and achievement with fellow competitors. Spots fill quickly, so be sure to secure your entry before the event reaches capacity.