A total of around 1,000 acres were listed for sale in South Dakota's Walworth County recently; the combined value of all Walworth County land and rural real estate for sale was $2 million. Walworth County ranks 43rd out of 66 counties in the Mount Rushmore State for the total number of acres of land currently advertised for sale. Selby featured the most land for sale. Walworth County is South Dakota's 45th biggest county (744 square miles). It's located in the Great Lakes South Dakota region of the state.