Lake Ontario drainage basin map

A map of the Lake Ontario drainage basin, which includes the St. Lawrence River drainage basin. There is a small inset showing the position of Lake Ontario relative to the other Great Lakes as the easternmost lake. The map's scale is in hundreds of kilometres and is oriented northward. It shows the Lake Ontario drainage basin on the left and the St. Lawrence drainage basin on the right.

The Canadian provinces shown are Ontario and Québec. The American state shown is New York. The international border between Canada and the United States runs along the boundary between Ontario and New York, through the middle of Lake Ontario and along the St. Lawrence River. Canadian cities shown (all in Ontario): Cornwall, Kingston, Belleville, Peterborough, Oshawa, Toronto, Hamilton, St. Catharines and Niagara Falls. American cities shown (all in New York): Niagara Falls, Rochester, Auburn, Syracuse, Watertown and Massena.

Also shown on the map are tributaries. Five unnamed tributaries to Lake Ontario are shown, with two along the northern coast of the lake in Ontario, one to the south-west coast in Ontario and two along the south coast in the state of New York.