Yankton, South Dakota Yankton, South Dakota Yankton is a city in, and the county seat of, Yankton County, South Dakota, United States. The population was 14,454 at the 2010 census. Yankton is the principal city of the Yankton Micropolitan Statistical Area, which includes the entirety of Yankton County, and which had an estimated population of 22,662 as of July 1, 2017. Yankton was the first capital of Dakota Territory. It is named for the Yankton tribe of Nakota (Sioux) Native Americans; Yankton is derived from the Nakota word "I-hank-ton-wan" ("the end village"). Yankton is located on the Missouri River just downstream of the
Native American recognition in the United States to be classified as Indian. At times a person's membership in a federally recognized tribe was not sufficient for classification as Indian in the eyes of the courts. The Major Crimes Act of 1885 placed seven major crimes under federal jurisdiction if committed by a Native American in Native American Territory. The Department of Justice required that a defendant be an enrolled member of a tribe to be covered by the Major Crimes Act. In his 1935 Memorandum to John Collier, Commissioner of Indian Affairs, the Assistant Solicitor, Felix S. Cohen, discussed the rights of a group of non-tribal Indians