from Fitchburg and Leominster to Lancaster. The Nashua River flows northward from Lancaster, meandering its way through the north-central Massachusetts towns of Harvard, Groton, Dunstable, and Pepperell, before eventually emptying into the Merrimack River at Nashua, New Hampshire. The Nashua River watershed has a total drainage area of approximately , with of the watershed occurring in Massachusetts and in New Hampshire. The Nashua River flows for approximately , with approximately 46 of those miles (74 km) flowing through Massachusetts. The Squannacook, Nissitissit, Stillwater, Quinapoxet, North Nashua, and South Nashua rivers feed it. The watershed encompasses all or part of 31 communities, 7 in southern New Hampshire and 24 in central Massachusetts. The watershed's largest water body is the Wachusett Reservoir, which provides drinking water to two-thirds of the Commonwealth's population. Major watershed components Wachusett Reservoir is the largest water body. The Stillwater River feeds Wachusett Reservoir from the northwest. The Quinapoxet River feeds Wachusett Reservoir from the west. Wachusett Reservoir Dam impounds the South Nashua River. The North Nashua River joins the South Nashua River at Lancaster from the northwest. The Squannacook River joins the Nashua River from the northwest at the junction of the town boundaries of Shirley, Groton, and Ayer. The Nissitissit River joins the Nashua River from the northwest at Pepperell. Major tributaries See also List of rivers of Massachusetts List of rivers of New Hampshire Nashua River Rail Trail Nashaway people References "The Promise of Restoration", National Geographic Magazine, November, 1993, Special Edition: Water. Parfit, Michael, "New Ideas, New Understanding, New Hope", National Geographic Magazine, November, 1993, Special Edition: Water. External links Nashua River Watershed Association Tributaries of the Merrimack River Rivers of Worcester County, Massachusetts Rivers of Middlesex County, Massachusetts Rivers of New Hampshire Nashua, New Hampshire Rivers of Hillsborough County, New Hampshire Rivers of Massachusetts Wild and Scenic Rivers of the United States Massachusetts placenames of Native American origin New Hampshire placenames of Native American origin