Saint John River

Saint John River, tributary (418 mi/673 km long) that rises in northwestern Maine and flows northeast to New Brunswick, where it makes up about 80 mi (129 km) of the U.S.-Canadian border. The river then turns south and east, flowing through New Brunswick to empty into the Bay of Fundy at St. John. It is famous for its “reversing falls,” made possible by exceptionally high Fundy tides.