Waldo 100K
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Waldo 100K
The Waldo 100K is a loop-type ultramarathon held in the Oakridge, Oregon area with a course based at Willamette Pass Ski Area (elevation 5120'). The route covers 100 kilometers and includes sustained climbs to several named peaks, including Fuji, The Twins, and Maiden Peak, before returning to the ski area.
The course is primarily single-track trail and contains some remote sections. Runners will pass viewpoints of Waldo Lake along the route. The organizer indicates the event is not a beginner-level ultra and recommends entrants have prior ultramarathon experience.
The 2026 edition used a lottery system for entries; the event also participated in a Trail to Zero program. When registering for the lottery, entrants had the option to contribute one dollar or more to a carbon offset program. A cited statistic notes that, across 29 mass participation events from 2014 to 2019, 98.5% of an event's carbon footprint came from participant travel.
Registration for the 2026 race closed on Wednesday, January 21, 2026 at 11:59 PM. Visit the organization's website for the most recent information.
