Oto (from Wat`ota, 'lechers'). One of the three Siouan tribes forming the Chiwere group, the others being the Iowa and Missouri. The languages differ but, slightly. The earliest reference to this tribe is found in the tradition which relates to the separation of the Chiwere group from the Winnebago. This tradition is given by Maximilian, who states that it was communicated to Maj. Bean, the Indian agent, by an old Oto chief. He related that, before the arrival of the whites a large band of Indians, the Hotonga ('fish-eaters'), who inhabited the lakes, migrated to the southwest in pursuit of buffalo. At Green Bay, Wis., they divided, the part called by the whites Winnebago remaining, while the rest continued the journey until they reached the Mississippi at the mouth of Iowa river, where they encamped on the sand beach and again divided, one band, the Iowa, concluding to remain there, and the rest continuing their travels reached the Missouri at the mouth of Grand river. These gave themselves the name of Neutache (`those that arrive at the mouth'), but were called Missouri by the whites. The two chiefs, on account of the seduction of the daughter of one by the son of the other, quarreled and separated one from the other. The division led by the father of the seducer became known as Waghtochtatta, or Oto, and moved farther up the Missouri. While the Winnebago settled in Wisconsin, the Iowa, after they ceded to the United States all the lands on which they first settled, moved west between Missouri river and the Little Platte. The Missouri, having been unfortunate in a war with the Osage, divided, and a part of them lived with the Iowa and a part with the Oto. The Oto continued up the Missouri until they crossed the Big Platte and lived for some time a short distance above its mouth; later they resided on Platte river, about 80 miles by water from the Missouri.
Marquette, in1673,apparently locates the tribe on his autograph map on upper Des Moines or upper Iowa river. Membré (1680) places them 130 leagues from the Illinois, almost opposite the mouth of the Wisconsin. Iberville (1700) said that the Otoand Iowa were then with the Omaha between the Missouri and Mississippi rivers, about 100 leagues from the Illinois. The last two statements agree substantially with that of Le Sueur. It is therefore not probable, as given in one statement, that the Oto were on Osage river in1687. That they were driven farther south by the northern tribes at a later date will appear from the list of localities given below. Lahontan claims to have visited their village in 1690 on the "Otentas [Iowa or Des Moines] river at its junction with the Mississippi," perhaps referring to a temporary camp.
In 1721, according to Charlevoix, the Oto were below the Iowa, who were on the E. side of Missouri river, and above the Kansa on the west side. Le Page du Pratz (1758) mentions the Oto as a small nation on Missouri river. Jefferys (1761) placed them along the south bank of "Panis river," probably the Platte between its mouth and the Pawnee country; but in another part of his work he locates them above the Kansa on the west side of Missouri river.
Lewis and Clark (1804) locate the tribe at the time of their expedition on the south side of Platte river, about 30 miles from its mouth, but state that they formerly lived about 20 miles above the Platte, on the south bank of the Missouri. Having diminished, probably through wars and smallpox, they migrated to the neighborhood of the Pawnee, under whose protection they lived, the Missouri being incorporated with them. From 1817 to 1841 they were on Platte river near its mouth. In the latter year they consisted of 4 villages. In 1880 a part of the tribe removed to the lands of the Sauk and Fox Indians in Indian Territory, and in 1882 the remainder left their home in Nebraska and went to the same reservation.