Lake Superior had many large islands in Robert Morden's 1698 map and John Senex' similar map of 1719. Even Guillaume de l'isle's map of 1718 showed an elevated plain.

Lake Superior's Agawa Rock, located in Ontario, is a site of profound spiritual and historical significance for indigenous peoples.

According to a U.S. Geological Survey study in 1993, the Nemadji has the highest sediment load of any Lake Superior tributary in Minnesota or Wisconsin -- about 131,000 tons of clay silt every year.