The formation of the Great Lakes

How they were made

Thousands of years ago, the melting mile-thick glaciers of the Wisconsin Ice Age left the North American continent a magnificent gift: five fantastic freshwater seas collectively known today as the Great Lakes — Lake Superior, Lake Huron, Lake Michigan, Lake Erie and Lake Ontario.

Lake Superior

The greatest of the Great Lakes is Lake Superior, the northernmost and westernmost Great Lake — and the biggest, the deepest, the coldest and the most pristine.

Lake Huron

The second-largest Great Lake, Lake Huron, has a surface area of 23,000 square miles — slightly smaller than West Virginia — making it the fifth-largest freshwater lake in the world.

Lake Michigan

Lake Michigan is the third largest Great Lake and the fifth largest lake in the world. Bordered by Wisconsin, Illinois, Indiana and Michigan, it is the only Great Lake that lies entirely within the boundaries of the U.S.

Lake Erie

Lake Erie is the fourth-largest Great Lake and the world’s twelfth largest freshwater lake. Erie is about 210 miles long, 57 miles wide and about 570 feet above sea level.

Lake Ontario

The opposite of Lake Superior in almost every way, Lake Ontario is the easternmost, lowest in elevation, smallest in surface area and perhaps the most polluted Great Lake.

Photo gallery

Great Lakes landscapes, cities, islands, bays and more.