Lake Superior other Great Lakes fish, populations have also been affected by the accidental or intentional introduction of foreign species such as the sea lamprey and Eurasian ruffe. Accidental introductions have occurred in part by the removal of natural barriers to navigation between the Great Lakes. Overfishing has also been a factor in the decline of fish populations. Lake Superior Lake Superior (; ), the largest of the Great Lakes of North America, is also the world's largest freshwater lake by surface area, and the third largest freshwater lake by volume. The lake is shared by the Canadian province of Ontario to
Lake Michigan Michigan is the sole Great Lake wholly within the borders of the United States; the others are shared with Canada. It lies in the region known as the American Midwest. Lake Michigan has a surface area of 22,404 sq.mi (58,026 km); (13,237 square miles, 34,284 km lying in Michigan state, 7,358 square miles, 19,056 km in Wisconsin, 234 square miles, 606 km in Indiana, & 1,576 square miles, 4,079 km in Illinois) making it the largest lake entirely within one country by surface area (Lake Baikal, in Russia, is larger by water volume), and the fifth-largest lake in the world.