Stony Brook
Stony Brook near its mouth in Wilton, NH
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Location
Country	United States
State	New Hampshire
County	Hillsborough
Towns	Greenfield, Lyndeborough, Wilton
Physical characteristics
Source	Lyndeborough Mountain
• location	Lyndeborough
• coordinates	42°55′14″N 71°48′19″W / 42.92056°N 71.80528°W / 42.92056; -71.80528
• elevation	1,270 ft (390 m)
Mouth	Souhegan River
• location	Wilton
• coordinates	42°50′39″N 71°44′20″W / 42.84417°N 71.73889°W / 42.84417; -71.73889
• elevation	338 ft (103 m)
Length	10.6 mi (17.1 km)

Stony Brook is a 10.6-mile-long (17.1 km)^[1] river located in southern New Hampshire in the United States. It is a tributary of the Souhegan River, which flows to the Merrimack River and ultimately to the Gulf of Maine.

Stony Brook rises in the town of Lyndeborough, New Hampshire, in a valley between Lyndeborough Mountain to the north and Winn Mountain to the south.^[2] It flows west into the town of Greenfield, then turns southeast and reenters Lyndeborough, continuing to the Souhegan in the mill town of Wilton.

It is paralleled from Greenfield to Wilton by New Hampshire Route 31 and by the former Hillsboro Branch of the Boston and Maine Railroad.

• List of rivers of New Hampshire