Are All Five Great Lakes Shared by Canada and the US?

No. Of the five Great Lakes, only Lake Michigan lies entirely within the United States. Lake Huron is often considered shared, but its Georgian Bay and North Channel are wholly in Canada; the main basin is bisected by the international border. Lake Superior, Lake Erie, and Lake Ontario are unequivocally shared, with the border running through their waters. Lake St. Clair (between Huron and Erie) is also shared. The Great Lakes Water Quality Agreement and other binational treaties govern joint management.