The main outlet of Lake Erie is the Niagara River.

The Niagara River flows from Lake Erie to Lake Ontario, passing over the famous Niagara Falls. This river serves as the primary outlet for Lake Erie, carrying water from the lake to the next stage in the Great Lakes water system. The flow of water from Lake Erie through the Niagara River is an important part of the natural hydrology of the region, and it also provides opportunities for hydroelectric power generation, particularly at the Niagara Falls power station.