Ontario and flows adjacent to Gananoque, Brockville, Morristown, Ogdensburg, Massena, Cornwall, Montreal, Trois-Rivières, and Quebec City before draining into the Gulf of St. Lawrence, one of the largest estuaries in the world. The estuary begins at the eastern tip of Île d'Orléans, just downstream from Quebec City. The river becomes tidal around Quebec City. The St. Lawrence River runs from the farthest headwater to the mouth and from the outflow of Lake Ontario. These numbers include the estuary; without the estuary, the length from Lake Ontario is c. 500 km (c. 300 mi). The farthest headwater is the North River in the Mesabi Range at Hibbing, Minnesota. Its drainage area, which includes the Great Lakes, the world's largest system of freshwater lakes, is , of which is in Canada and is in the United States. The basin covers parts of Ontario and Quebec in Canada, parts of Minnesota, Wisconsin, Illinois, Indiana, Ohio, Pennsylvania, New York, Vermont, and nearly the entirety of the state of Michigan in the United States. The average discharge below the Saguenay River is . At Quebec City, it is . The average discharge at the river's source, the outflow of Lake Ontario, is . The St. Lawrence River includes Lake Saint-Louis south of Montreal, Lake Saint Francis at Salaberry-de-Valleyfield and Lac Saint-Pierre east of Montreal. It encompasses four archipelagoes: the Thousand Islands chain near Alexandria Bay, New York and Kingston, Ontario; the Hochelaga Archipelago, including the Island of Montreal and Île Jésus (Laval); the Lake St. Pierre Archipelago (classified a biosphere world reserve by the UNESCO in 2000) and the smaller Mingan Archipelago. Other islands include Île d'Orléans near Quebec City and Anticosti Island north of the Gaspé. It is the second longest river in Canada. Lake Champlain and the Ottawa, Richelieu, Saint-Maurice, Saint-François, Chaudière and Saguenay rivers drain into the St. Lawrence. The St. Lawrence River is in a seismically active zone where fault reactivation is believed to occur along late Proterozoic to early Paleozoic normal faults related to the opening of the Iapetus Ocean. The faults in the area are rift-related and comprise the Saint Lawrence rift system. According to the United States Geological Survey, the St. Lawrence Valley is a physiographic province of the larger Appalachian division, containing the Champlain and Northern physiographic section. However, in Canada, where most of the valley is, it is instead considered part of a distinct St. Lawrence