Great Lakes Megalopolis the Chicago-Rochester corridor, starting at the Detroit River but continuing east beyond Lake Ontario along the St. Lawrence Seaway to Quebec City and the Gulf of St. Lawrence. Several corridors have interstate highways but no comprehensive passenger rail service. These highway routes pass through both core and fringe areas of the Great Lakes megalopolis. The upper Great lakes region has a marine corridor that connects Lakes Superior, Huron, and Michigan. However, this route does not include parallel Amtrak passenger rail or interstate highway service. I-70 follows the southern fringe of the megaregion. It runs from Kansas City MO to just
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