Louisiana was discovered by French explorer Robert Cavalier Sieur De La Salle on April 9, 1682. La Salle made the discovery out of Canada by way of the Mississippi River, and returned the same way. In 1684, he was sent back by way of the Atlantic Ocean into the Gulf of Mexico to find the mouth of the Mississippi River. Unfortunately, on March 20, 1687, he was assassinated by his disenchanted men in what is now Texas.

Source: Buddy Stall at http://clarionherald.org/20000120/stall.htm