Ziebach County, South Dakota
Ziebach County (Zee-bahk) is a county in the U.S. state of South Dakota. As of the 2020 census, the population was 2,413. Its county seat is Dupree. It is the last county (or county equivalent) in the United States alphabetically.
Ziebach County consists entirely of Indian reservations. Most of the county is within the Cheyenne River Indian Reservation and the remainder is within the Standing Rock Sioux Reservation.