There are bodies of water in Ontario.
Lake of the Woods ( lac des Bois ) is a lake occupying parts of the Canadian provinces of Ontario and Manitoba and the U.S. state of Minnesota . Ontario . Almost all of Ontario 's 2700 km border with the United States follows inland waterways : from the west at Lake of the Woods , eastward along the major rivers and lakes of the Great Lakes/Saint Lawrence River drainage system . These are the Rainy River , the Pigeon River , Lake Superior , the St. Marys River , Lake Huron , the St. Clair River , Lake St. Clair , the Detroit River , Lake Erie , the Niagara River , Lake Ontario and along the St. Lawrence River from Kingston , Ontario , to the Quebec boundary just east of Cornwall , Ontario .