During the season, more than 4,000 cargo vessels passed through, carrying almost 75 million tons of iron ore, coal, grain and other commodities.
The government said roughly 3,200 tour boats, private boats and other recreational vessels used the locks during the 2011 season. The locks on the St. Marys River allow boats and ships to pass between Lake Superior and the lower Great Lakes. Traffic stops in winter because of ice.
The locks should reopen by March 25.