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A Trip down the Cold River

Mill dam

The Cold River begins in the hills of northwest Acworth and Unity at Crescent Lake (1215 feet above sea level). Over its 22 mile course from the Crescent Lake dam to the Connecticut River in Walpole the river drops 979 feet.

The Cold River tumbles first as a stream over the small dam at the east end of Crescent Lake. This first 1.3 miles is the river’s steepest stretch, with a gradient dropping 66 ft/mile. The river slows next to meander through the marsh that was once a mill pond behind the old Keyes Hollow dam.

Below the Deep Hole to the river's end, the valley broadens and the Cold River’s swift current carries it over a cobbled river bottom with an average gradient of 40 ft/mile. It crosses under McDermott Covered Bridge in Langdon before entering Vilas Pool, created by a dam at the head of a small gorge. Vilas Pool is a popular place for picnicking, boating, swimming and many summer events in the town of Alstead. Water flowing

The river flows through Alstead and its valley broadens again. After several miles, the valley walls close sharply and the river drops over the spectacular Drewsville Gorge, where 25 foot cliffs rise above several small waterfalls. Below this gorge, the Cold River cuts through deep sand and gravel deposits that once formed a great delta in the ancient glacial Lake Hitchcock.

As the Cold River joins the Connecticut , it deposits its own sand and gravel in a sand bar that sweeps into the larger and slower Connecticut .

What is a Watershed?

A watershed consists of all of the land area that contributes water to a specific body of water.  The Cold River Watershed is the land surface that serves as the drainage system for the Cold River.  It includes all of the land uphill from the Cold River’s lowest point, where the Cold River empties into the Connecticut River near Route 12 in Walpole.

The Cold River Watershed includes 102 square miles of Acworth, Alstead, Charlestown, Langdon, Lempster, Marlow, Unity and Walpole.  It contains water bodies such as Lake Warren, Crescent Lake, Vilas Pool and a multitude of ponds and streams, including about a dozen major feeder streams (or “tributaries”).  Each of the lakes, ponds and streams has its own sub-watershed within the Cold River Watershed.

Rain that falls on the watershed (and is not intercepted by plants or evaporated) drains to the Cold River both through and over the ground.  Water flowing through the ground is extracted from wells and springs for drinking, and also receives treated wastewater from our septic systems.  Water flowing overland in streams is used for both wildlife habitat and recreation, and is diverted for fire supply and other important purposes.     

Within the Cold River Watershed, the flow of water winds across town and property boundaries in response to physical, chemical and biological factors.  In this place, water connects us all in one way or another – we are all upstream or downstream of someone else.  This connection requires us to be good neighbors and stewards of the environment. 

As a result, many state and federal agencies are recognizing that the management of land use is most effectively done on a watershed basis.  The Cold River Local Advisory Committee is working with those agencies as well as local boards and residents to promote land use practices and regulations compatible with watershed protection. 

For more information on NH watersheds, go to