Which explorer traveled to the carolinas and Oklahoma and found the Mississippi river?

The explorer who traveled to the Carolinas and Oklahoma and is credited with discovering the Mississippi River is Hernando de Soto. He explored parts of the southeastern United States in the 1530s, making significant contributions to the European understanding of the region. De Soto's expeditions included traversing areas that are now part of the Carolinas and ultimately led him to the banks of the Mississippi River, which he crossed in 1541.