Waldo 100K
Always double-check with the organizer's website! This page may contain affiliate links.
Waldo 100K Ultramarathon
The Waldo 100K is an ultramarathon on a 100-kilometer loop course. It starts and finishes at the Willamette Pass Ski Area, located about 70 miles east of Eugene, Oregon. The start is at an elevation of 5,120 feet.
The course climbs several mountains, including Fuji, The Twins, and Maiden Peak. The route is mostly on single-track trails, with some remote sections. It offers views of Waldo Lake. The organizers state it is not a beginner-level ultramarathon and recommend participants have prior experience.
In 2026, the event used a lottery system for registration.
The event is part of Ultrasignup's Trail to Zero™ carbon offset program. During lottery registration, participants can optionally contribute one dollar or more to this program to offset travel-related emissions. Visit the organization's website for the most recent information.
