Lake Erie is the fourth-largest of the Great Lakes by surface area and the shallowest and smallest by volume. It lies on the international border between Canada and the United States, with Ontario on its northern shore and Michigan, Ohio, Pennsylvania, and New York bordering its western, southern, and eastern shores. The lake is the southernmost of the Great Lakes and, at its deepest point, reaches only about 210 feet (64 m).
Erie is fed chiefly by the Detroit River, which carries water from Lake Huron. Its principal outflow is the Niagara River, which connects it to Lake Ontario and passes over Niagara Falls. Part of the flow is also diverted through the Welland Canal, a key shipping route in the Saint Lawrence Seaway. The lake’s largest city is Cleveland, while other major shore cities include Buffalo, New York, Erie, Pennsylvania, and Toledo, Ohio.
Because of its relatively shallow depth, Lake Erie is easily stirred by winds and is known for strong storms, seasonal water-level changes, and hazardous navigation. Its shores and harbors have long required dredging and other maintenance because of shoaling and erosion. The lake also freezes over in winter around its harbors and outlets, though the lake itself does not freeze completely.
Lake Erie has long been important for transportation, shipping, and regional commerce, and its fertile surrounding lands support fruit production, especially grapes and peaches. In modern times, its environmental health has been a recurring concern, particularly in relation to pollution, overfishing, algae blooms, invasive species, and eutrophication.