Blackwater Dam is a dam in the town of Webster, Merrimack County, New Hampshire.

The earthen dam was constructed in 1941 by the United States Army Corps of Engineers with a height of  and  long at its crest.  It impounds the Blackwater River for flood control and storm water management as one of five related projects in the Merrimack River basin.  The dam is owned and operated by the New England District, North Atlantic Division, Army Corps of Engineers.

The seasonal flood-control reservoir created by the dam has a maximum capacity of , but is normally dry, apart from the normal flow of the Blackwater.  The site includes  of river popular for canoeing and kayaking, and fishing for brown and rainbow trout.

References 

Dams in New Hampshire
Reservoirs in New Hampshire
United States Army Corps of Engineers dams
Dams completed in 1941
Buildings and structures in Merrimack County, New Hampshire
Landforms of Merrimack County, New Hampshire
Webster, New Hampshire