The Pleasant River is a 13.1 miles (21.1 km) tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 of the Presumpscot River

Presumpscot River

The Presumpscot River is a river located in Cumberland County, Maine. It is the main outlet of Sebago Lake.-Course:The river flows through the communities of Standish, Windham, Gorham, Westbrook, Portland, and Falmouth before emptying into Casco Bay at Falmouth...

 in the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Maine

Maine

Maine is a state in the New England region of the northeastern United States, bordered by the Atlantic Ocean to the east and south, New Hampshire to the west, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is both the northernmost and easternmost...

.

The Pleasant River originates in the town of Gray

Gray, Maine

Gray is a town in Cumberland County, Maine, United States. The population was 6,820 at the 2000 census. It is part of the Portland–South Portland–Biddeford, Maine metropolitan statistical area. Gray is home to regional headquarters for the Maine Department of Inland Fisheries and...

 and parallels U.S. Route 202

U.S. Route 202

U.S. Route 202 is a highway stretching from Delaware to Maine, also passing through the states of Pennsylvania, New Jersey, New York, Connecticut, Massachusetts, and New Hampshire....

 as it flows southwesterly through the town of Windham

Windham, Maine

Windham is a town in Cumberland County, Maine, United States. The population was 17,001 at the 2010 census. It includes the villages of South Windham and North Windham...

 to discharge into the Presumpscot River upstream of the village of South Windham.

Water power

Early water power surveys found suitable locations at Jackson's Falls or Huston's Falls (where grist, shook, and lumber mills were constructed) near the Gray-Windham town line, a 10 feet (3 m) drop at Varney's Falls where a sawmill was constructed near the Route 202 bridge, an 8 feet (2.4 m) drop at Anderson's Falls where a sawmill was constructed near the road from Windham Center to Windham Hill, a 10 feet (3 m) drop at Pope's Falls (where lumber, corn, flour, grist, wool carding, and cloth weaving mills were constructed) near Popeville, a 7 feet (2.1 m) drop at Allen's Falls where a sawmill was constructed, and a 10 feet (3 m) drop at Baker's Falls where a stave mill was constructed. Colonel Edward Anderson increased flow through these falls by diverting additional water to the Pleasant River through the moraine

Moraine

A moraine is any glacially formed accumulation of unconsolidated glacial debris which can occur in currently glaciated and formerly glaciated regions, such as those areas acted upon by a past glacial maximum. This debris may have been plucked off a valley floor as a glacier advanced or it may have...

 at the south end of Little Sebago Lake. Water power was developed at the moraine and on the resulting Ditch Brook where a stave mill was built on the Varney Mill Road above the confluence with Pleasant River at the U.S. Route 302

U.S. Route 302

U.S. Route 302 is a spur of U.S. Route 2. It currently runs 171 miles north from Portland, Maine, at U.S. Route 1, to Montpelier, Vermont, at US 2...

bridge.

Flooding

The outlet control structure at the south end of Little Sebago Lake failed on 4 June 1814, and within a few hours water draining to the Pleasant River eroded a channel through the moraine, dropping the lake elevation 50 feet (15.2 m). The resulting flood swept away two mills and six bridges along the Pleasant and Presumpscot rivers as far downstream as South Windham. Drainage from Little Sebago Lake was permanently diverted from Outlet Brook into the Pleasant River by destruction of the moraine, although the lake level was partially restored by construction of a stone dam at the narrows in 1860. That dam failed with similar downstream damage on 7 May 1861, but has subsequently been rebuilt.