12hr ultramarathons in United States (Midwest)

Nighttime endurance laps on an illuminated dirt horse track at Harrison County Fairgrounds with continuous chip timing and flexible distance

Half-mile pine forest loop in Lowell Park, continuous 6, 12, or 24-hour format with self-supported setup and solo or team options

Crushed limestone loops circling Miola Lake with well-stocked aid stations in a low-key, supportive ultramarathon setting

Overnight run on a 1.5-mile paved loop around Smith Park, community-focused event in historic Middletown

Paved 4-mile loop at Mill Creek Park, scenic starts and finishes by J.C. Nichols Memorial Fountain, well-stocked aid station each lap

Historic Blackhawk Ski Club loop with 367 feet of gain per 2.25-mile lap, 50-foot pines, spring pool, rope swing, and climb beneath the ski jump

Challenging 12-hour last runner standing on a 4.1-mile rugged trail loop amid summer heat at Comlara parks, testing endurance, pacing, and strategy

Demanding 1.1-mile loop with 140 feet of elevation gain per lap, steep climbs on Hogsback Lane, a mix of paved and singletrack in Rocky River Reservation

Repeated 1.5-mile farm loop on flat dirt and pasture, surrounded by miniature animals, with variable trail conditions and on-site camping options.

One-mile loop on a wide, gently rolling path of gravel, grass, and dirt with 72 feet of elevation gain per loop, illuminated for nighttime laps.

Scenic 1-mile paved loop in a 58-acre city park, rotating hourly challenges, 6- or 12-hour format, solo or relay options, central aid station and vendor

Looped course through Fargo and Moorhead parklands, varied terrain, multiple bridge crossings, and extensive aid between laps

1.2-mile loop course, flexible durations up to 24 hours, single aid station, relaxed community atmosphere, nighttime running with quiet hours enforced

24-hour race with accurate timing, emphasizing competition, personal achievement, and camaraderie on a runner-designed course

12-hour loop featuring bike path, grass, and trail terrain in Dayton, Montgomery

Flat, roughly mile-long loop with field, wooded trail and pavement, plus a small mound each lap; steady rhythm over long hours

2.07-mile gravel and concrete loop at Arrowhead Lake Campground with minimal elevation, designed for speed and high mileage in Johnston City, IL.

Endurance challenge spanning daylight hours, designed for participants to push physical limits from sunrise to sunset