The Hamsterwheel is a timed trail-running event in New Boston, New Hampshire, held in November on a marked 4-mile loop near the Hillsborough County Fairground. Participants select solo or relay formats, with race durations from 6 hours up to 30 hours. The objective is straightforward: complete as many laps as possible within your chosen category's time limit.
The loop utilizes the New Boston Rail Trail and has runners as straightforward, not technical. This emphasizes pacing, nutrition, and mental fortitude over navigating difficult terrain. Spectators and support crews can observe runners every 4 miles, a benefit for ultrarunners. The event has seen significant mileage achieved, such as Cody Cutler's 144 miles in the 30-hour race, completed after 36 out-and-back segments on the rail trail.