Their name for themselves was K'itaish, and they are most closely related to the Pawnee. French explorers encountered them on the Red River in Louisiana in 1701.
The Kitsai were part of the complex, shifting political alliances of the South Plains. Early Europeans identified them as enemies of the Caddo. In 1712, they fought the Hainai along the Trinity River; however, they were allied with other member tribe of the Caddoan Confederacy and intermarried with the Kadohadacho during this time.
By 1772, they primarily settled east of the Trinity River, near present day Palestine, Texas.
Sturtevant, William C., general editor and Raymond D. Fogelson, volume editor. Handbook of North American Indians: Southeast. Volume 14. Washington DC: Smithsonian Institution, 2004. ISBN 0-16-072300-0.