Congratulations, Boulderthon Finishers! Race Results & Photos are here.


Running is the heartbeat of Boulder — one of the three hallmark recreational activities of our community (along with cycling and hiking, of course).

Together, we run the streets & trails of Boulder, and serve as one of the great training grounds for Olympians, world-class athletes, and leisure runners alike. We are so grateful & proud to have the world's best 10k — but despite running being hardwired into Boulder’s DNA — we have no signature city marathon.

This was the question we asked everyone — and we couldn’t find out why.

In one of the great health meccas of the US, rated one of the healthiest, happiest cities in the country, we couldn’t find a premier long-distance marathon.

After years in the making and the opportunity to acquire a 19-year-old race series, the Boulder Backroads Marathon & Half Marathon, we knew the time was now. As residents of Boulder County and local business owners, our goal from day 1 has been to create an inspiring, community-driven marathon series to serve as the premier fall race in the state. We decided to create the epic, downtown marathon race the beautiful city and community of Boulder deserves.

The Boulderthon® was born.


Course Maps & Elevations may be adjusted based on covid-19 safety modifications, local and state recommendations, and higher-than-anticipated registration numbers to accommodate a larger participant count, and provide the best overall runner, spectator, and Boulder County & City of Boulder resident experience. If you have any questions, feedback, or suggestions, please do not hesitate to contact us at

Interactive Course Map

Half Marathon Course Map & Elevation
Full Marathon Course Map & Elevation