Great Lakes Island, Harsens Island, Manitoulin Island, and the Toronto Islands. As of 2007, four car ferry services cross the Great Lakes, two on Lake Michigan: a steamer from Ludington, Michigan, to Manitowoc, Wisconsin, and a high speed catamaran from Milwaukee to Muskegon, Michigan, one on Lake Erie: a boat from Kingsville, Ontario, or Leamington, Ontario, to Pelee Island, Ontario, then onto Sandusky, Ohio, and one on Lake Huron: the M.S. Chi-Cheemaun runs between Tobermory and South Baymouth, Manitoulin Island, operated by the Owen Sound Transportation Company. An international ferry across Lake Ontario Rochester, New York, to Toronto ran during 2004 and
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