Nissitissit River
Nissitissit River in Brookline, New Hampshire
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Location
Country	United States
States	New Hampshire, Massachusetts
Counties	Hillsborough, NH, Middlesex, MA
Towns	Brookline & Hollis, NH; Pepperell, MA
Physical characteristics
Source	Potanipo Pond
• location	Brookline, NH
• coordinates	42°44′10″N 71°40′20″W / 42.73611°N 71.67222°W / 42.73611; -71.67222
• elevation	264 ft (80.5 m)
Mouth	Nashua River
• location	Pepperell, MA
• coordinates	42°40′18″N 71°33′53″W / 42.67167°N 71.56472°W / 42.67167; -71.56472
• elevation	168 ft (51 m)
Length	10.5 mi (16.9 km)
National Wild and Scenic River
Type	Scenic
Designated	March 12, 2019

The Nissitissit River is a 10.5-mile-long (16.9 km)^[1] river in southern New Hampshire and northern Massachusetts in the United States. It is a tributary of the Nashua River, itself a tributary of the Merrimack River, which flows to the Gulf of Maine. This river is part of the Nashua River Watershed.

The Nissitissit River begins at the outlet of Potanipo Pond in the town of Brookline, New Hampshire. It flows southeast at a very mild gradient, crossing the southwest corner of Hollis, New Hampshire, before entering Massachusetts, where it joins the Nashua River in the town of Pepperell.

• List of rivers of Massachusetts
• List of rivers of New Hampshire