The Territory of Mississippi was an organized incorporated territory of the United States that was created under an organic act signed into law by President John Adams on April 7, 1798. It was dissolved on December 10, 1817, when the western half of the territory was admitted to the Union as the State of Mississippi. The eastern half was redesignated as the Alabama Territory; it was admitted to the Union as the State of Alabama on December 14, 1819. The Chattahoochee River played a significant role in the definition of the territory's borders. The population increased in the early 1800s from settlement, with cotton being an important cash crop.

The history of the state of Mississippi extends back to thousands of years of indigenous peoples. Evidence of their cultures has been found largely through archeological excavations, as well as existing remains of earthwork mounds built thousands of years ago. Native American traditions were kept through oral histories; with Europeans recording the accounts of historic peoples they encountered. Since the late 20th century, there have been increased studies of the Native American tribes and reliance on their oral histories to document their cultures. Their accounts have been correlated with evidence of natural events.