Erie, Lake, 9,940 sq mi (25,745 sq km), 241 mi (388 km) long and from 30 to 57 mi (48–92 km) wide, bordered on the N by S Ont., Canada, on the E by W N.Y., on the S by NW Pa. and N Ohio, and on the W by SE Mich. and NW Ohio.; fourth largest of the Great Lakes. It is 572 ft (174 m) above sea level with a maximum depth of 210 ft (64 m), making it the shallowest of the Great Lakes and the only one with a floor above sea level.
Lake Erie is part of the Great Lakes–St. Lawrence Seaway system and is linked to Lake Huron by the Detroit River, Lake St. Clair, and St. Clair River, and with Lake Ontario by the Niagara River (Lake Erie's only natural outlet) and the Welland Canal. The New York State Canal System links the lake with the Hudson River. Several small rivers, including the Maumee, Sandusky, and Cuyahoga, flow into the lake from the south; the Grand River enters from Ontario. Lake Erie is partially icebound in winter and is usually closed to navigation from mid-December to the end of March.
Rich agricultural lands border the Canadian shore, where the chief towns are Port Colborne and Port Stanley. The principal U.S. cities on the lake are Buffalo, Erie, Cleveland, and Toledo; all are ports with heavy industry. Numerous recreation facilities are provided at national, provincial, and state parks located on the lake's islands and shores.
Untreated industrial and municipal wastes from lakeshore cities—and from Detroit, whose wastes enter the western end of the lake—polluted the waters and rendered surrounding areas foul smelling. A U.S.-Canadian pact (1972) ended the discharge of contaminating materials into the water, and the environmental damage abated. In the early 21st cent., however, an increase in phosphorus from agricultural runoff contributed to large algal blooms in the lake; the algae's decomposition also created significant oxygen-depleted "dead zones" on lake bottom.
The first European to see the lake was French explorer Louis Jolliet in 1669. The British and the French, and later the British and the Americans, fought for its control. The battle of Lake Erie (Sept. 10, 1813), a naval engagement in the War of 1812, led successfully by the U.S. leader Oliver H. Perry against the British, was fought at Put-in Bay.