Mountain Lakes 100
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Event overview
Mountain Lakes is a 100-mile trail ultramarathon held in the Oregon Cascades with a start and finish at Olallie Lake Resort. The route runs largely on the Pacific Crest Trail between Mt. Jefferson and Mt. Hood, including roughly 60 miles on the PCT. The course contains technical and rocky sections, multiple lake views and mountain vistas, and about 11,700 feet of total ascent and descent. The course low point is about 3,300 feet and the high point is about 5,700 feet. The race date is September 19-20, 2026, and there is a 30-hour time limit.
Logistics, requirements and rules
Field capacity is 150. Registration tiers are tiered by date and the organizer publishes nontransferable entries with no refunds; cancellations more than 30 days before the race receive a 50% credit toward a future event, cancellations within 30 days receive no credit. All entrants and waitlisters must complete eight hours of trail work after October 1 and by September 1 and submit a signed form; entrants without completed hours may forfeit their spot. Cell and internet service are very limited along the course; organizers use paper tracking and HAM radio at aid stations. The event is on National Forest multi-use trails where horses may be encountered. Parking at Olallie Lake Resort is limited and managed with short-term, long-term, and restricted road-side options; long-term parking has a $20 cash fee and no RVs or trailers in that lot. Visit the organization's website for the most recent information.