Land for sale in Clay County, Kansas, recently totaled nearly $5 million and almost 1,000 acres. Clay County ranks 90th in the Wheat 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, Clay Center had the most land for sale. Clay County is the 73rd largest county (655 square miles) in Kansas. It's located in the Tallgrass Prairie Kansas region of Kansas.