Lake Ontario is the eastern-most and smallest in surface area (18,960 square kilometers) of the Great Lakes. It exceeds only Lake Erie in volume. Its primary inlet is Niagara Falls and primary outlet is the St. Lawrence River. Other notable geographic features are Hamilton Harbour, the Bay of Quinte, and the Toronto Islands
The southern, American shore of the lake is largely rural, with the exception of Rochester, New York. A few large and medium-sized cities (notably Toronto and Hamilton, Ontario) are to be found on the Canadian side.