Statistics for occurrence #1 of “Yanktonai Sioux” in entry yankton-indians of Harper's Encyclopedia of United States History:
...tribe of the Siouan family.
In 1899 there were 1,061 lower Yanktonai Sioux at the Crow Creek agency, in South Dakota; 1,239 Yanktonai Sioux at Fort Peck agency, in Montana; a considerable number of Yanktonai Sioux at the Standing Rock agency, in North Dakota; and 1,728 Yankton Sioux at the Yankton agency, in South Dakota.
For further details of this tribe, see Sioux, or Dakota, Indians.
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