Lake Erie (//; French: Lac Érié) is the fourth largest lake (by surface area) of the five Great Lakes in North America, and the tenth largest globally or twelfth largest globally if measured in terms of surface area. It is the southernmost, shallowest, and smallest by volume of the Great Lakes and therefore also has the shortest average water residence time. It is bounded by Ontario to the north, Ohio, Pennsylvania, and New York to the south, and Michigan to the west. The lake is named after the Erie tribe of Native Americans who lived along its southern shore. The outflow from the lake provides hydroelectric power to Canada and the U.S. as it spins huge turbines at Niagara Falls. The lake's environmental health has been an ongoing concern for decades, with issues such as overfishing, pollution and more recently algal blooms and eutrophication generating headlines.
The Great Lakes (sometimes, Laurentian Great Lakes) are a series of interconnected freshwater lakes located in northeastern North America, on the Canada–United States border, which connect to the Atlantic Ocean through the Saint Lawrence Seaway. Consisting of Lakes Superior, Michigan, Huron (or Michigan–Huron), Erie, and Ontario, they form the largest group of freshwater lakes on Earth, containing 21% of the world's surface fresh water. The total surface is 94,250 square miles (244,106 km2), and the total volume (measured at the low water datum) is 5,439 cubic miles (22,671 km3). Due to their sea-like characteristics: rolling waves, sustained winds, strong currents, great depths, and distant horizons, the five Great Lakes have also long been referred to as inland seas. Lake Superior is the largest continental lake in the world by area, and Lake Michigan is the largest lake that is entirely within one country.
The Great Lakes began to form at the end of the last glacial period around 10,000 years ago, as retreating ice sheets carved basins into the land and they became filled with meltwater. The lakes have been a major highway for transportation, migration and trade, and they are home to a large number of aquatic species. Many invasive species have been introduced due to trade, and some threaten the region's biodiversity.