Ruth Anderson Memorial Endurance Run

The Ruth Anderson Memorial Endurance Run is an ultradistance race held annually in San Francisco, California, at scenic Lake Merced. The course features a mostly flat, USATF-certified 4.48-mile loop on paved paths and groomed dirt shoulders around the lake, with about 100 feet of elevation gain per loop. Runners can choose to compete in 50 kilometers, 50 miles, or 100 kilometers, with aid stations stocked with water, electrolytes, and food available each loop.

The race offers a supportive atmosphere with access to personal supplies at the aid station and a single turnaround point for the 50-mile distance. All finishers receive a commemorative patch and car sticker. Visit the organization's website for the most recent information.