Run Denver’s springtime race! The Colfax Marathon has a distance for everyone with seven races over two days in the Mile High City. The 26.2 mile Marathon runs through Denver’s iconic landmarks: Mile High Stadium (twice), Sloan’s Lake, City Park, Colfax Avenue – and so much more. The Colfax Half Marathon is the only race to run through Denver Zoo. Enjoy uniquely Colorado entertainment along the route. Celebrate lakeside in Denver’s City Park after the race.