There are bodies of water in Ontario.
The Great Lakes ( les Grands-Lacs ) , also called the Laurentian Great Lakes and the Great Lakes of North America , are a series of interconnected freshwater lakes located primarily in the upper mid-east region of North America , on the Canada -- United States border , which connect to the Atlantic Ocean through the Saint Lawrence River . Ontario . Ontario is bordered by the province of Manitoba to the west , Hudson Bay and James Bay to the north , and Quebec to the east and northeast , and to the south by the U.S. states of ( from west to east ) Minnesota , Michigan , Ohio , Pennsylvania and New York . 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 .