Boulder Co 2024 Marathon 2024. In 2024, usa today named boulderthon’s 5k the #5th best in the country, while simultaneously announcing its half marathon as the #8th best in the us, in its 2024. Find and register for your next full marathon race with our calendar.

Use our marathon calendar to find and compare all colorado marathons.  — this epic race experience takes runners through the foothills of the iconic flatirons in boulder, co.