Ontario contains The Rainy River.
Ontario . 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 . The Rainy River ( French : Rivière à la Pluie ; Ojibwe : Gojiji-ziibi ) is a river , approximately 137 km long , which forms part of the Canada -- United States border separating northern Minnesota and Northwestern Ontario .