Lake Michigan tour boats will return to Michigan City in northern Indiana for the first time since 1949, beginning June 2. Here are five interesting facts about Lake Michigan.

It’s old

Lake Michigan was formed during the last Ice Age as glaciers advanced and then retreated across the region, creating large glacial lakes.

An all-American lake

Lake Michigan is one of the five Great Lakes of North America and the only one located entirely within the United States. The other four Great Lakes are shared by the U.S. and Canada.

It’s big and deep

Lake Michigan is the third largest Great Lake by surface area and the sixth largest freshwater lake in the world. It has a surface area of 22,404 square miles and is the second-largest of the Great Lakes by volume at 1,180 cubic miles. The lake’s average depth is 279 feet, and its greatest depth is 923 feet.

Shared by 4 states

Lake Michigan is shared, from west to east, by the U.S. states of Wisconsin, Illinois, Indiana and Michigan.

The ‘Third Coast’

Lake Michigan has many beaches. The region is often referred to as the “Third Coast” of the United States, after those of the Atlantic Ocean and the Pacific Ocean. With more than 275,000 acres of sand dunes lining the shores of Lake Michigan, Michigan is home to the largest freshwater dune system in the world.