Source of Mississippi River Was Found by Henry Schoolcraft in 1832. He named the Minnesota body of water Lake Itasca. The Mississippi River flows south 2,350 miles from Lake Itasca to the Gulf of Mexico. It is the world’s fourth longest river system (after the Nile River, the Amazon River, and the Yangtze River). Children could find some VERY INTERESTING FACTS at: http://www.nps.gov/miss/riverfacts.htm.