The reservation occupies the easternmost 60 percent of Charles Mix County in southeastern South Dakota, United States and abuts the Missouri River along its southwest border.

It has a land area of 665.712 sq mi (1,724.186 km2) and a total area (land and water) of 684.406 sq mi (1,772.604 km2), and a resident population of 6,500 persons as of the 2000 census.

The largest community on the reservation is the city of Wagner, which is the location of the tribal headquarters.

The blues-rock group Indigenous is originally from this community, as is early 20th-century author and activist Zitkala-Sa.

[5] Media related to Yankton Indian Reservation at Wikimedia Commons