A total of nearly 1,000 acres were listed for sale in Clay County recently; the combined value of all Clay County ranches, farms, hunting land and other rural land and acreage for sale was around $14 million. Clay County ranks 14th out of 66 counties in the Mount Rushmore State for the total number of acres of land currently advertised for sale. Of all locations in Clay County with farms, ranches, hunting land and other land for sale, Vermillion featured the most land for sale. Government and state-level services are the main economic drivers in Clay County. Clay County is the 66th largest county (417 square miles) in South Dakota. It's located in the Southeast South Dakota region of South Dakota.