Clay County is in Southeast South Dakota. Of the 66 counties in the Coyote State, 417-square-mile Clay County ranks 66th by size. Clay County, South Dakota, includes around 1,000 acres of residential land for sale based on recent Land Network data. The combined market value of ranches, farms, hunting land and other rural land and acreage for sale here was approximately $7 million. The average price of residential acreage for sale in Clay County was $300,021. 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.