The Pine Ridge Indian Reservation (Wazí Aháŋhaŋ Oyáŋke in Lakota, also called Pine Ridge Agency) is an Oglala LakotaNative Americanreservation located in the U.S. state of South Dakota. Originally included within the territory of the Great Sioux Reservation, Pine Ridge was established in 1889 in the southwest corner of South Dakota on the Nebraska border. Today it consists of 3,468.85 sq mi (8,984.306 km2) of land area and is the eighth-largest reservation in the United States, larger than Delaware and Rhode Island combined.