The value of land for sale in Clay County recently on Land.com was almost $800,000. This represents approximately 1,000 acres of farms, hunting land and other rural land and acreage for sale in Clay County. Clay County ranks 97th out of 102 counties in the Inland Empire for the combined amount of land currently advertised for sale. Among cities in Clay County with farms and rural real estate for sale, Flora featured the most land for sale. From an economic perspective, manufacturing and related services are the main sectors in Clay County. Clay County is Illinois's 60th biggest county (469 square miles). It's located in the Southern Illinois region of the state.