The Bear River is a 2.7 miles (4.3 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 Long Lake

Long Lake (Maine)

Long Lake is an eleven mile lake between the towns of Naples, Maine, Bridgton, Maine and Harrison, Maine. It is connected to Brandy Pond through the Chute River. Long Lake was created by receding glaciers, and has many coves and rocks....

 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...

. It originates at the outlet of Bear Pond in the town of Waterford

Waterford, Maine

Waterford is a town in Oxford County, Maine, United States. The population was 1,455 at the 2000 census. It is a recreation area noted for historic architecture and scenic beauty.-History:...

 in Oxford County

Oxford County, Maine

Oxford County is a county located in the U.S. state of Maine with a population of 57,833 as of the 2010 U.S. census. Its county seat is Paris.Part of Oxford County is included in the Lewiston-Auburn, Maine, metropolitan New England City and Town Area while a different part of Oxford County is...

, then flows southeast into the town of Bridgton in Cumberland County

Cumberland County, Maine

Cumberland County is a county located in the U.S. state of Maine. As of 2010, the population was 281,674. Its county seat is Portland, and is the most populous of the sixteen Maine counties, as well as the most affluent. Cumberland County has the deepest and second largest body of water in the...

 and finally the town of Harrison

Harrison, Maine

Harrison is a town in Cumberland County, Maine, United States. The population was 2,315 at the 2000 census. A historic resort area, Harrison straddles Long Lake and Crystal Lake...

, where it reaches Long Lake. Via Long Lake, the Songo River

Songo River

The Songo River is a river in Maine with the only remaining operational lock of the Cumberland and Oxford Canal. The river flows from Brandy Pond at the south end of Long Lake into Sebago Lake at Sebago Lake State Park. Songo Lock controls the elevation of Long Lake and allows navigation of...

, and Sebago Lake

Sebago Lake

Sebago Lake is the deepest and second largest lake in the U.S. state of Maine. The lake is deep at its deepest point, with a mean depth of , covers about in surface area, has a length of and a shoreline length of . The surface is around above sea level, so the deep bottom is below the present...

, the Bear River is part 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...

 watershed, flowing to Casco Bay

Casco Bay

Casco Bay is an inlet of the Gulf of Maine on the southern coast of Maine, New England, United States. Its easternmost approach is Cape Small and its westernmost approach is Two Lights in Cape Elizabeth...

 on the Atlantic Ocean

Atlantic Ocean

The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

.