Backyard ultramarathons in Michigan, United States

4.167-mile trail loop by day, paved park road by night, hourly starts, no outside aid, last runner standing format inspired by Laz Lake

24-hour backyard ultra with a 4.167-mile loop through Upper Peninsula woods, featuring gravel, rooty singletrack, rolling ski trails, and 289 feet of elevation

Timed races on 2-mile dirt and trail loops with loop count challenges, plus a Last One Standing endurance test on a flat gravel course

Scenic 4.167-mile loop in Sleepy Hollow State Park, with prairie, hardwood forest and pine, modest climbing, and classic last-runner-standing format

One-mile wooded loop with 150 feet of climb per lap, sandy downhill across an open field, varied terrain, and repeat rounds on private land near Big Rapids