October ultramarathons in Iowa, United States

Rugged 50k trail course with creek crossings, steep climbs, and about 750 feet of elevation gain per loop through scenic Swiss Valley Nature Preserve

48-hour format with 4-mile loops every 4 hours on mixed paved trails and disc golf course terrain, featuring night running and optional bonus lap

Steep climbs, technical paths, and flat prairie trails on a looped course through forests and bluffs, featuring river views in Iowa's driftless region.

Rails to Trail course along the Wabash Trace Nature Trail, starting and finishing at Iowa West Foundation Trail Head Park

Flat, paved 1.9-mile loop at Gray's Lake Park with minor rolling hills; age and gender equalized scoring; 6, 12, or 24-hour race options