Islands

The second-largest island is in Lake Superior. Both of these islands are large enough to contain multiple lakes themselves — Manitoulin Island's is listed in the Guinness Book of World Records as the world's largest lake located on a freshwater island.

Dispersed throughout the Great Lakes are approximately. The largest among them is in Lake Huron, the largest island in any inland body of water in the world.

The Great Lakes are also connected to the Gulf of Mexico by way of the (from the and the Mississippi River. An alternate track is via the Illinois River (from Chicago), to the Mississippi, up the Ohio, and then through the (combination of a series of rivers and lakes and canals), to and the Commercial tug-and-barge traffic on these waterways is heavy.