Boulderthon
September 27 @ 7:00 am - 2:30 pm
Boulderthon returns to downtown Boulder on Sunday September 27, 2026, with a marathon, half marathon, 10K, the Heart to Heart 5K and a Kids Run. The Start Village opens at 5:00 a.m. on the Pearl Street Mall between 13th and 15th, the marathon and half start at 19th and Pearl at 7:00 a.m., and everything finishes at 14th and Pearl. The course is 98 percent paved roads and multi-use path, measured by a Level A USATF course measurer, USATF sanctioned and a Boston qualifier, with the marathon running out past Boulder Reservoir onto county backroads. Field capacity is 15,000 and the marathon has sold out in past years. Aid stations sit roughly every two miles, the cutoff is six hours, and the finish festival runs until 2:30 p.m.
