Sisseton is a city on the Lake Traverse Indian Reservation in Roberts County, South Dakota, United States. The population was 2,470 at the 2010 census. It is the county seat of Roberts County. Sisseton is home to a number of attractions including the Nicollett Tower and is near the "Song to the Great Spirit" building on the campus of Sisseton Wahpeton College. Named for the Sisseton (or Sissetowan) division of the Native American Sioux, the city is located a few miles north of the tribal seat of the Sisseton Wahpeton Oyate at Agency Village, South Dakota.
Sisseton is located at 45°39′48″N 97°2′57″W / 45.66333°N 97.04917°W / 45.66333; -97.04917 (45.663259, -97.049040).
According to the United States Census Bureau, the city has a total area of 1.6 square miles (4.1 km²), all of it land.