The Welland Ship Canal is a 27-mile ship canal traversing the Niagara Peninsula between Lake Ontario and Lake Erie, bypassing Niagara Falls. It forms a key portion of the St. Lawrence Seaway allowing for the marine transport of goods and commodities from the Midwestern United States to the St. Lawrence River and the Atlantic Ocean. Ships with a maximum length of 720 feet, maximum beam of 78 feet and a maximum air draught of 116 feet can pass through eight locks, taking an average of eleven hours to navigate the altitude change of 326 feet between Lake Ontario and Lake Erie. The first Welland Canal was begun in 1824 and opened in 1829. The fourth (current) Welland Canal was completed in 1932.