The Great Lakes make up 84% of North America’s surface fresh water and about 21% of the world’s supply of surface fresh water.

The Great Lakes water system is the largest inland shipping system in the world.

The only Great Lake entirely within the U.S. is Lake Michigan.

Lake Michigan’s shores hold the largest fresh water sand dunes in the world.

The Great Lakes were formed due to glacial movements that caused depressions in the earth that eventually filled with water.

Lake Michigan and Lake Huron are considered one lake hydrologically since they are connected by the Straits of Mackinac.

Although it falls under the category of what we define as a lake, Lake Superior acts more like an inland sea.

There are 9,000-year-old animal-herding structures below Lake Huron.

The Lake Huron shoreline extends 3,827 miles and encompasses 30,000 islands. It is the longest shoreline of the Great Lakes.

The water in Lake Erie is recycled every 2.6 years, the shortest of any Great Lake.