Great Lakes is the world's largest lake located on a freshwater island. Some of these lakes even have their own islands, like Treasure Island in Lake Mindemoya in Manitoulin Island The Great Lakes also have several peninsulas between them, including the Door Peninsula, the Peninsulas of Michigan, and the Ontario Peninsula. Some of these peninsulas even contain smaller peninsulas, like the Keweenaw Peninsula, the Thumb Peninsula, the Bruce Peninsula, and the Niagara Peninsula. Population centers on the peninsulas include Grand Rapids, Michigan, Detroit, Michigan, London, Ontario, Hamilton, Ontario, and Toronto, Ontario. The Saint Lawrence Seaway and Great Lakes Waterway make the Great
Great Lakes pass the locks on the Saint Lawrence Seaway because the ships are too wide. Only four bridges are on the Great Lakes other than Lake Ontario because of the cost of building structures high enough for ships to pass under. The Blue Water Bridge is, for example, more than 150 feet high and more than a mile long. The Great Lakes are used to supply drinking water to tens of millions of people in bordering areas. This valuable resource is collectively administered by the state and provincial governments adjacent to the lakes, who have agreed to the Great Lakes Compact