On this day in 1852, President Millard Fillmore signed legislation that allowed for a canal and lock to be built at Saulte Ste. Marie (Ontario and Michigan) that would connect the St. Mary’s River to Lake Superior, allowing ship traffic from New York to the Head of the Lakes. (The St. Mary’s River connects with Lake Huron and, therefore, all of the lower Great Lakes.) The locks bypass a stretch of the river filled with rapids that drop 21 feet. The locks opened in 1855, a year after the signing of the 1854 Treaty of La Pointe, which in part first opened what is now the Minnesota side of Lake Superior to settlement by non-native people. Superior was established before the locks opened, and by 1856 many of those who first went to Superior began establishing townsites in what is now the city of Duluth. When Duluth finally established itself as a city in 1870, those locks helped bring people and goods to the Zenith City, and when the wheat fields of the Red River Valley opened the locks (along with the Duluth Ship Canal and the Lake Superior & Mississippi Railroad) helped turn Duluth into a major grain-trading center. Coal and immigrants flowed to Duluth from the east, and the Zenith City sent grain and later iron ore to the east. Much of this continues to this day, but now the coal comes from the west and is shipped east. Read about the coal industry in Duluth here.