Caddoan Mississippian culture
The Caddoan Mississippian culture was a prehistoric Native American culture considered by archaeologists as a variant of the Mississippian culture. The Caddoan Mississippians covered a large territory, including what is now Eastern Oklahoma, Western Arkansas, Northeast Texas, Southwest Missouri and Northwest Louisiana of the United States.
Source: Wikipedia — Caddoan Mississippian culture (CC BY-SA 4.0)