Great Lakes Circle Tour through the province, running the entire length from the Peace Bridge to the Ambassador Bridge. Unlike the other four Great Lakes, Lake Ontario is posted not as a circle tour but as part of the US-only Seaway Trail. The trail begins in Erie County, Pennsylvania and travels through Buffalo, Niagara Falls, Rochester, Oswego, and Ogdensburg before ending at the Seaway International Bridge near Massena. Plans for the Great Lakes Circle Tours were started in 1985. The Michigan Department of Transportation (MDOT) was in consultation with its counterparts in Wisconsin (WisDOT), Minnesota (MnDOT) and Ontario (Ministry of Transportation of Ontario, MTO)
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