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Ruth Anderson Memorial Endurance Run

Lakeshore, United States • 11 Oct 2025

Ruth Anderson Memorial Endurance Run is an ultramarathon held in San Francisco, California, circling Lake Merced. Runners complete a multi-lap course on a 4.475-mile paved bike path, with aid stations at the start/finish and each loop. The event features distances associated with a 50M designation, including time cutoffs after 7 and 10 laps, reaching roughly 31 to 45 miles; the history also notes a 100k/50k distance in records. The course offers USATF-certified maps and relies on a dedicated team of Race Directors and volunteers, with support from SF Rec & Parks and Tailwind Nutrition. The atmosphere is community-minded and historic, drawing steady annual participation since 1986. Visit the organization's website for the most recent information.

United States California Lakeshore

Race information

Website
100 km
100k
50 mi
50 Miles
50 km
50k
Visit the organization's website for the most recent information.
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