A most northwesterly and largest of the five Great Lakes of North America and one of the world's largest bodies of fresh water. Bounded on the east and north by Ontario (Can. ), on the west by Minnesota (U. S. ), and on the south by Wisconsin and Michigan (U. S. ), it discharges into Lake Huron at its eastern end via the St. Marys River. The lake is 350 mi (563 km) long (east to west), and its greatest width is 160 mi (258 km) from north to south.