Missouri Indians, a tribe of the Chiwere division of the Siouan language group. They lived in what is now northern Missouri. After 1800, wars and epidemics greatly reduced their numbers, and by 1842 they had moved to southeastern Nebraska. In 1882 the Missouri and Oto were removed to Indian Territory (now Oklahoma). There were only 13 Missouri in 1910, and afterward they were classified with the Oto.