Flat Rock Trail Race
Dunstable, United States • 13 Jun 2026
Flat Rock Trail Race : Dunstable, MA
Flat Rock Trail Race is a trail running event held in Dunstable, Massachusetts that benefits the Humane Society for Greater Nashua. The event offers a standard 5-mile race on a marked loop and a 6-hour format in which participants may complete as many laps as they can within six hours.
Distances
- 5 Mile loop
- 6 Hour unlimited laps within time limit
The course is a roughly 5-mile loop with nearly 600 feet of elevation gain per lap. The route crosses the Arched Bridge in the Arched Bridge Conservation Area, follows part of the former Nashua, Acton and Boston Railroad bed, passes around a former granite quarry and farm, and includes climbs to the tops of the old Blanchard Hill Ski Area and Flat Rock Hill. The loop is described as well marked.
Entry fees are treated as donations to the Humane Society for Greater Nashua. There are no refunds or deferrals. The event is planned to take place rain or shine. Organizers note permission and support from the Dunstable Conservation Commission, the Dunstable Rural Land Trust, and the Town of Dunstable. Volunteer signups are scheduled to open in late April. Registration closes on Thu, Jun 11 at 11:59 PM ET. Visit the organization's website for the most recent information.