The Kansa, after whom the state and river are named, were related to the Osage, Quapaw, Ponca, and Omaha tribes; spoke a similar (Central Sioux) language; and had migrated with them from the Ohio Valley.  Like the Osage, the Kansa lived in permanent villages of long, bread-shaped thatched lodges near fields of maize, beans, and squash.  Their territory was beautiful, and Lewis and Clark said they saw several parakeets near the site of Kansas City.  The Expedition also collected the last rare plant sample from that region on its return trip in mid-September 1806. 

Kansa men harvested thousands of deer each year, which the women brain-tanned for clothing and trade.  The Kansa also hunted buffalo on the Great Plains every summer, and St. Louis merchants always wanted their buffalo robes and "grease."  The French had been trading with the Kansa since the 1720s and operated a fur fort near their villages in the 1740s and 1750s.  

The Kansa in 1804 were a small tribe of about 1,300 people.  Their 300 warriors were only one-fifth as many as the Osage, but they were fierce fighters.

The Kansa had a bad reputation as robbers of white traders along the Missouri River, which may have been one reason why Lewis and Clark advised the U.S. government to build an army fort in the Kansas City area.  (Fort Leavenworth was founded there in 1827.)   Kansa lands in northeastern Kansas also became the first "Indian Territory" west of the Mississippi, where thousands of Native Americans from the East would be resettled by the 1830s.  Forced to move themselves due to Pawnee raids and white settlers, the Kansa gave two million acres of their land to the United States.