Plain Endurance Runs

Plain Endurance Runs take place in Leavenworth, Washington, on September 19, 2026. Two trail formats start together at 5:00 a.m.: a 100-mile and the Plain 100K (62 miles). The 5:00 a.m. start hints at long days for both fields. The organizer's website is plain100.com, and Leavenworth sits on the eastern slopes of the Cascades.

Both distances are substantial mountain ultras. The 100K makes sense as a step up from a 50-mile, while the 100-mile belongs to runners with prior 100K or 100-mile experience who are comfortable with self-sufficiency and night running. Plan a 20-week build with weekly long trail runs, back-to-back weekends, regular hiking on steep ground and thorough fueling rehearsals. Navigation and gear management deserve as much attention as your mileage: check the race rules on markings and required equipment well before the event, because mountain ultras like this one often ask more of you in those areas than a typical trail race.