The Welland Canal is a ship canal in Canada that extends 42 km (26 mi) from Port Weller, Ontario, on Lake Ontario, to Port Colborne, Ontario, on Lake Erie. As a part of the St. Lawrence Seaway, this canal enables ships to ascend and descend the Niagara Escarpment and to bypass Niagara Falls.
Approximately 40,000,000 tonnes of cargo are carried through the Welland Canal annually by a traffic of about 3,000 ocean and Great Lakes vessels. This canal was a major factor in the growth of the city of Toronto. The original canal and its successors allowed goods from such Great Lakes ports as Detroit, Cleveland, Windsor, and other heavily industrialized areas of the United States and Ontario to be shipped to the port of Montreal or to Quebec City, where they were usually reloaded onto ocean-going vessels for international shipping.
The completion of the Welland Canal made the Trent-Severn Waterway, that connected Lake Ontario with Lake Huron, obsolete as a commercial traffic route for Great Lakes navigation.
The southern terminus of the Welland Canal on Lake Erie, located at Port Colborne, is 99.5 meters (326.5 feet) higher than the northern terminus of the Canal at Port Weller on Lake Ontario. This canal includes eight ship locks, each of which is 24.4 meters (80 feet) wide by 233.5 meters (766 feet) long. The Garden City Skyway passes over the canal, restricting the maximum height of the masts of the ships allowed on this canal to 35.5 meters (116.5 feet).
All other highway or railroad crossings of the Welland Canal are either movable bridges (of the vertical lift or bascule bridge types) or subterranean tunnels. The maximum permissible length of a ship in this canal is 225.5 meters (740 feet). It takes ships an average of about eleven hours to traverse the entire length of the Welland Canal.