09/26/2026
Boulder knows a thing or two about running. 🏃♀️⛰️
Boulderthon returns Sunday, September 27, bringing thousands of runners to Boulder for one of Colorado’s premier fall race weekends.
With a marathon, half marathon, 10K, 5K and Kids Run, there’s something for serious runners, families and everyone who would rather cheer from the sidelines. And with Boulder’s mountain views, fall scenery and the energy of Downtown Boulder, this is one race weekend that feels distinctly local.
📅 Sunday, September 27
📍 Boulder, Colorado
🏁 Finish-line festivities in Downtown Boulder
Whether you’re running, cheering or simply enjoying the excitement around town, Boulderthon is a great reminder of why Boulder’s active, outdoor lifestyle is such a big part of this community.