The Spirit Lake Tribe (in Santee Dakota: Mni Wakan Oyate, formerly Devils Lake Sioux) is a federally recognized Sisseton Wahpeton tribe based on a reservation located in east-central North Dakota on the southern shores of Devils Lake. Established in 1867 in a treaty between Sisseton Wahpeton Bands and the United States government, the reservation, at (47°54′38″N98°53′01″W), consists of 1,283.777 km² (495.669 sq mi) of land area primarily in Benson and Eddy counties.