Of 66 counties in the Coyote State, Sully County is 29th in terms of its size (1,070 square miles). Sully County is in Great Lakes South Dakota. Recent Land Network data includes nearly 1,000 acres of riverfront property for sale in South Dakota's Sully County, which is valued at a combined $8 million. Browse all waterfront property for sale in Sully County on the Land Network to find the marina, lakefront and other recreational property that meets your needs, from waterside land perfect as a retirement investment to existing residential waterfront land and property for hunting, fishing and other outdoor-recreation pursuits! By overall acreage, undeveloped land is the most common type of land for sale in Sully County.