Boulder Half Marathon 2024 Registration. On sunday, september 29th, 2024 for the fourth annual boulderthon marathon in stunning boulder, colorado. Sign up for boulderthon 2024:
You’ll start and finish in the iconic running mecca of downtown boulder, with stunning views of the flatirons throughout the course. Attracting athletes from all over the west due to its phenomenal scenery, glamorous finisher medals, perfect running temperatures with.