The Eternal Damnation Backyard is Kansas' original backyard ultra, run on the Switchgrass bike trail at Wilson State Park near Sylvan Grove. It uses the classic last-runner-standing format: every runner gets one hour to finish a 4.167-mile loop, then starts again on the next hour until only one person can answer the bell. Speed matters less than the ability to recover, refuel, and decide to go out for one more lap. The field averages about 75 runners, and the event is presented by Ultraverse Supplements.
The loop starts with about three-quarters of a mile on pavement so the pack can spread out, then moves onto hilly single-track mountain bike trail. Overall the course is about 25% pavement or road and 75% single track, with 92 meters of climbing each loop at roughly 441 meters of altitude. Tim Fryer is the Yardmaster, and the race culture is loose but stubborn: runners who are done are encouraged to stay, cheer for the survivors, and watch with a BYOB beer while the remaining field keeps shrinking.