The Oto (Chewaere, Hoctatas, Octatas) lived in eastern Nebraska on the lower course of the Platte River and along the Missouri River. They now live in a federal trust area in northcentral Oklahoma together with the Missouri. They speak a Chiwere Siouan language and number close to two thousand.
Whitman, William (1937). "The Oto." Columbia University Contributions to Anthropology 23:1-32.