The Lake Traverse Indian Reservation is the homeland of the federally recognized Sisseton Wahpeton Oyate, a branch of the Santee Dakota group of Native Americans. Most of the reservation covers parts of five counties in northeastern South Dakota, while smaller parts are in two counties in southeastern North Dakota, United States. Its largest com…The Lake Traverse Indian Reservation is the homeland of the federally recognized Sisseton Wahpeton Oyate, a branch of the Santee Dakota group of Native Americans. Most of the reservation covers parts of five counties in northeastern South Dakota, while smaller parts are in two counties in southeastern North Dakota, United States. Its largest community is the city of Sisseton, South Dakota.