Named among the Best Fall Marathons by Runner's World, #5 Best Half Marathon in the US by Active, as well as #1 Best in Colorado and one of the "Most Beautiful Marathons in the World" by HalfMarathons.Net, Boulderthon drew over 10,000 runners from all 50 states and 18 countries in 2024, and has doubled in size every year since its inception.
In 2024 and 2025, USA TODAY named Boulderthon’s 5K among the Top 10 best in the country, while simultaneously announcing its Half Marathon as the #8th best in the US, in its 2024 10Best Readers’ Choice awards. The lists are curated by USA Today 10Best editors reviewing thousands of races across the country, narrowing it down to the top 20 in each category by a panel of expert runners, and then voted on by readers to determine the winners.
Tucked into a picturesque valley below the iconic Flatirons, Boulder, Colorado sets the backdrop for the top-ranked, signature Boulder Marathon, Boulderthon. Boulder is a world-class destination offering 300 days of sunshine and endless recreation, shopping, dining, cultural and entertainment choices. It's no wonder National Geographic named Boulder the Happiest City in America.
Feel on top of the world!
Boulder is a world-class destination offering 300 days of sunshine and endless recreation, shopping, dining, cultural and entertainment choices. It's no wonder National Geographic named Boulder the Happiest City in America.
“Racing in Boulder, Colorado, should be on every runner's bucket list, and the Boulderthon Half Marathon might be the perfect way to cross it off. The course starts at Boulder Reservoir, which gives you a true sense of Colorado's scenic beauty. Then you run along the foothills of the Flatirons. Finally, you wind your way into downtown Boulder and finish on the historic Pearl Street Mall.
Veteran runners have touted this as one of the best race events of their lives; it has all the amenities of a big race (gear check, pace groups, plentiful aid stations) with the charm and attention to detail of a small race. Plus, it's a downhill finish!” - Active.com
