The Welland Canal connects Lakes Ontario and Erie. Because of the difference in elevation between the Atlantic and the Great Lakes, a system of canals and locks was required to allow large boats to navigate the connected waterways. (A lock is a section of a canal that can be closed to control the water level and it is then used to either raise or lower a vessel to another body of water). The Welland Ship Canal is part of this system. It lies entirely within the Canadian province of Ontario, extending 27 miles (43 kilometers) from Port Weller on Lake Ontario (the eastern-most of the Great Lakes) to Port Colborne on Lake Erie. The natural waterway that connects these two bodies is the Niagara River. The height difference of the two lakes (Lake Erie is 326 feet or 99 meters higher than Lake Ontario) makes Niagara's spectacular waterway of falls and rapids unnavigable. The original Welland Canal was completed in 1829. Built by a private company that had secured government loans, the project cost nearly 8 million dollars. In 1833 an extension to the canal was completed. Six years later, Upper Canada (today the province of Ontario) took over the Welland to enlarge the canal to accommodate bigger ships. That project was completed by 1845; a second enlargement was undertaken in 1887. The Canadian government has continued to improve the waterway since. It remains the vital link for shipping between the nation's interior and the Atlantic Ocean.
See also: Erie Canal, Soo Locks