Statistics for occurrence #1 of “South Dakota” in entry yankton-indians of Harper's Encyclopedia of United States History:

...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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Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
South Dakota (South Dakota, United States) 435 247 1 1 0 user votes

† This entity has been selected by the automated classifier as the most likely match in this context. It may or may not be the correct match.