North Fork 50K

2026

The North Fork 50K takes place in late May in Buffalo Creek, Colorado, about 50 miles southwest of Denver. This single-loop course covers just over 31 miles with roughly 3,670 feet of climbing, running entirely on soft surface trails through the Pike National Forest at altitudes between 6,700 and 8,150 feet. The route moves through sections of beautiful ponderosa pine forest alongside areas burned in the 1996 Buffalo Creek fire, creating an interesting contrast between shaded singletrack and more exposed terrain with expansive mountain views. You'll encounter granite rock formations and wind along Buffalo Creek itself, with the course described as quite runnable for those comfortable with mountain trails and altitude. The mostly singletrack route includes some doubletrack sections and stays technical enough to keep things interesting without being overly demanding. Runners who enjoy mountain ultras but prefer something more approachable than the bigger, more intimidating Colorado races will find this fits well. The 13-hour cutoff is generous, making it a solid choice for first-time trail ultramarathoners or those looking to test their legs at altitude. If you're not used to running above 6,000 feet or prefer flatter, faster courses, the combination of elevation and climbing might feel more challenging than the relatively modest numbers suggest.