Shipping on the Great Lakes

• The St. Lawrence Seaway opened in April of 1959.
• The Seaway extends 2,340 miles (3,700 km) from the Atlantic Ocean to the head of the Great Lakes.
• The Seaway includes a system of locks that lift ships up and down over three areas where barriers to shipping are encountered.
• The Seaway system is connected by 6 short canals with a total length of less than 60 nautical miles (111 km).
• There are 19 locks, filled and emptied by gravity.
• Ships measuring up to 740 feet in length (225 m) and 78 feet (24 metres) in the beam are routinely raised to more than 590 feet (80 metres) above sea level, as high as a 60-story building.
• The ships are twice as long and half as wide as a football field and carry cargoes the equivalent of 27,500 tons (25,000 tonnes).
• Each lock is 766 feet (234 metres) long, 80 feet (24 m) wide and 30 feet (9 m) deep over the sill.
• A lock fills with approximately 24 million gallons (91 million L) of water in just 7 to 10 minutes.
• Getting through a lock takes about 45 minutes.
• Annual commerce exceeds 200 million net tons (180 million net tonnes). 
* It is estimated that between 6,000 and 10,000 ships have sunk or been stranded on the Great Lakes since the early 1800s.