We are sorry to have to make the very difficult, but necessary announcement that Boulderthon's October 11th, 2020 edition has been postponed to April 25th, 2021. Though we have worked tirelessly over the last few months to produce Boulderthon safely this Fall, we have ultimately had to make the decision for the health & safety of all our runners, staff, and volunteers who have so generously and enthusiastically believed in our race and have signed up to participate.

We could not be more grateful for your support, and like all of us, never expected to have to face this in our first year as we launched our community's new signature Boulder Marathon series. As I'm sure many of you know from our correspondence together and the amazing training runs you have shared with us, please know that this decision did not come lightly, and the Boulderthon team has truly explored every angle and possible format to attempt to bring our new race series and downtown marathon experience to life this Fall.

For all those who have put the work in already with those training runs, you can still register for the #VirtualBoulderthon and run from anywhere in October, and earn that coveted Finisher Medal and Finisher T-Shirt. You may also now request your new Race Date for the next in-person editions of Boulderthon, which will occur on April 25th, 2021, October 10th, 2021, and October 9th, 2022.

We truly appreciate all your support, and please don't hesitate to reach out with any questions at hi@boulderthon.org. -- Phil Dumontet, Race Director


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.


The Official Boulderthon™ Course Map will be released 30 days prior to Race Day on April 21st, 2021, which will include a detailed overview of Medical & Aid Stations, Spectator Cheer Spots, Toilets, Starting & Finish Line Amenities, as well as our on-course Eldorado & Skratch Labs Hydration & Nutrition. Our Strava Routes 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 hi@boulderthon.org.