The Nashua River Rail Trail is a 12.5-mile paved mixed-use rail trail in northern Massachusetts and southern New Hampshire under control of the Massachusetts Department of Conservation and Recreation (DCR). It sits on the former Hollis branch of the Boston and Maine Railroad and roughly follows the course of the Nashua River, passing through the towns of Ayer, Groton, Pepperell, and Dunstable, Massachusetts, ending about a mile across the New Hampshire state border into the city of Nashua. The trail is used by walkers, cyclists, inline skaters, equestrians, and cross-country skiers.