Named #5 Best Half Marathon in the US by Active, as well as #1 Best in Colorado and #13 Most Beautiful Marathon in the World by HalfMarathons.Net, Boulderthon drew over 4,000 runners from all 50 states and 15 countries in 2022, nearly tripling in registration, and selling out.
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.
Boulderthon Full Marathon
Run the Boulder Marathon in the happiest, fittest city in the US! Includes Finisher Medal, Finisher Shirt, 1 Free Beer, Timing Chip.
Boulderthon Half Marathon
Run the Boulder Marathon in the happiest, fittest city in America! Includes Finisher Medal, Finisher Shirt, 1 Free Beer, Timing Chip.
Bookend your season with a fun 10K! Includes Finisher Medal, Finisher Shirt, Timing Chip.
Run a fun, fast 5K! Includes Finisher Medal, Finisher Shirt, and Timing Chip.
Boulderthon Kids Run
Run Boulder's 2nd annual Kids Run! Includes Kids Finisher Medal and Kids Finisher Shirt.
"I've run nearly 50 marathons and/or half marathons and this ranks among the very best. Race day execution was flawless and I echo the previous comments about the professional staff and well organized volunteers groups. Looking forward to next year already!"
"Great Day, Great Race. I can’t imagine a marathon that is run any better. Everything went well, volunteers were plentiful and helpful, aid stations were great, and the weather was perfect for a long run. And Boulder turned out in force to cheer us on."
"This was by far one of the best races I’ve participated in - Aid stations were dispersed well and there was so much help and encouragement from the volunteers and police officers. Thank you thank you thank you."
"Fun course, positive vibes, beautiful views and just enough support along the way. Thanks to all who helped make this race happen. I’ll be back every year. Perfect Race."
"Fantastic Race. Great job to all who organized this event. You knocked it out of the park! From the great communications, well organized packet pick ups, friendly aid and water stations, and after party."
"Terrific race, beautiful course. Staff and volunteers were first class all the way!"
95% of runners would recommend to their friends, with #1 reason being Downtown Finish & Course Views.
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