Though the five lakes have separate basins, they form a single, connected body of freshwater. The lakes connect the east-central interior of North America to the Atlantic Ocean. Lakes Michigan, Huron and Erie are approximately equally high and ships can easily pass from one to the next. Water flows from Lake Superior and Lake Michigan into Lake Huron; then through the Detroit River into Lake Erie; then through Niagara Falls into Lake Ontario; and then through the Saint Lawrence River to the Atlantic Ocean. Water also drains from the Chicago River on the south.