Boulderthon 2026: The Boulder Marathon

A boutique marathon nestled in the foothills of the Rockies with stunning views throughout the course, Boulderthon offers a marathon, half marathon, plus an all-new, all-roads 10K, and 5K, as well as a Kids Run. With the goal of spreading the joy and power of running and creating a more inclusive community, Boulderthon caters to all ages and abilities, and gives you the chance to experience the magic of the running mecca of Boulder, plus run against the stunning backdrop of Colorado’s Flatiron mountains!

The marathon course starts in vibrant downtown Boulder, goes up past the Boulder Reservoir, and back down into Beautiful Downtown Boulder, finishing on Spruce, at the heart of our Finish Festival.

Half marathon runners will follow a similar route, beginning on Pearl Street turning around 8.8 miles in and heading back down to Pearl St!

The 10K is the perfect fall race, with a route taking in the streets of Downtown Boulder and some of the amazing views offered by the city. You’ll head along Pearl Street and then onto Pearl Parkway, where you’ll be spurred on by live music! Just after Valmont City Park, you’ll loop back towards downtown Boulder, following the same route and then finishing on Spruce.

This speedy 5k is an all-roads course, starting and finishing in downtown Boulder. The 5K is the flattest, fastest roads 5K prize purse and boasts one of the largest 5K prize purse in the nation at over $40,000.

Returning for its sixth year, the popular kids' run starts at 21st and Pearl and ends with an incredible finish on the historic Pearl Street Mall! Parents can run for free with their child, so this is the perfect introduction to running for your little ones.