Nashua River

Nashua River
Nashua River, just outside Groton, Massachusetts
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Location
Country	United States
States	Massachusetts, New Hampshire
Counties	Middlesex, MA Hillsborough, NH
Towns and cities	Lancaster, Shirley, Ayer, Groton, Pepperell (MA), Hollis, Nashua (NH)
Physical characteristics
Source	Confluence of North Nashua River and South Nashua River
• location	Lancaster, MA
• coordinates	42°26′50″N 71°40′9″W / 42.44722°N 71.66917°W / 42.44722; -71.66917
• elevation	233 feet (71 m)
Mouth	Merrimack River
• location	Nashua, NH
• coordinates	42°45′58″N 71°26′49″W / 42.76611°N 71.44694°W / 42.76611; -71.44694
• elevation	95 feet (29 m)
Length	37.5 mi (60.4 km)
Basin size	108 square miles (280 km2)
Discharge
• average	150 cu ft/s (4.2 m3/s)
Basin features
Tributaries
• left	Squannacook River, Nissitissit River
• right	Still River
National Wild and Scenic River
Type	Scenic
Designated	March 12, 2019[1]

The Nashua River, 37.5 miles (60.4 km) long,^[2] is a tributary of the Merrimack River in Massachusetts and New Hampshire in the United States. It is formed in eastern Worcester County, Massachusetts, at the confluence of the North Nashua River and South Nashua River, and flows generally north-northeast past Groton to join the Merrimack at Nashua, New Hampshire. The Nashua River watershed occupies a major portion of north-central Massachusetts and a much smaller portion of southern New Hampshire.

The North Nashua River rises west of Fitchburg and Westminster. It flows about 30 miles (48 km) generally southeast past Fitchburg, and joins the South Nashua River,^[3] shown on USGS topographic maps as the main stem of the Nashua River,^[4] about 5 miles (8 km) below its issuance from the Wachusett Reservoir.