Clay County is in Southeast South Dakota. Of the 66 counties in the Mount Rushmore State, Clay County is 66th in terms of its size (267,148 acres). The total value of nearly 1,000 acres of residential land recently listed for sale in Clay County, South Dakota, was around $6 million. The average price of residential land for sale in Clay County was $264,750. Browse all residential land and rural property for sale in South Dakota to find residential land and properties that suit your lifestyle needs, from existing residential homes and estates to land ready for future residential-property development.