Ocean freighters reach Duluth through a binational ladder of locks
The St. Lawrence Seaway threads rivers, canals, and locks from Montreal to Lake Erie so Atlantic ships can sail inland as far as Duluth on Lake Superior. Opened in 1959 at a cost of C$470 million—Canada paid $336.2 million—it still markets itself as “Highway H2O.”.
Welland Canal ancestors opened in 1824 and, after enlargements through 1935, offered 7.6-metre depth and locks 233.5 by 24.4 metres. Comprehensive deep-water proposals dated from the 1890s, tying navigation to hydropower. A 1932 treaty failed U.S. Senate ratification in 1934. Impatient Canada authorised its own Seaway Authority in December 1951; Eisenhower signed the Wiley-Dondero Act on 13 May 1954. Ground broke at Massena, New York, that August. Queen Elizabeth II, John Diefenbaker, and Eisenhower formally opened the route on 26 June 1959 aboard HMY Britannia after speeches at Saint-Lambert.
Seven river locks plus the Welland system lift Seawaymax ships—740 by 78 feet—deliberately smaller than 1914 Panamax dimensions because designers matched the 1932 Welland. Some 22,000 workers built the 3,700-kilometre “superhighway.” In 2002, vessels moved 222 million tonnes of cargo; overseas steel and grain were only 6.9% of that total. U.S. business revenue around Great Lakes–seaway shipping runs about $3.4 billion a year. Grain export patterns later shifted toward Gulf and West Coast ports as Europe ceased to dominate demand.
Critics once blamed the seaway for killing the Erie Canal and Upstate New York towns, yet railroads had already undercut canal freight by 1900. A Corps of Engineers expansion study died in 2011 over budget. Low Great Lakes levels from 2010 to 2016 worried operators. The Canada Marine Act of 1998 recast Canadian sections as non-profit corporations. Twin authorities—Canadian and American—still advertise the shared ditch that finally let saltwater keels kiss Superior.
Source: St. Lawrence Seaway
