A total of around 2,000 acres were listed for sale in Williamson County recently, representing a combined around $52 million in Williamson County farms, rural land, hunting land and other land for sale. Williamson County ranks 16th in Illinois for the total acreage of land currently advertised for sale. Among cities in Williamson County with farms, rural land, hunting land and other land for sale, Marion featured the most land for sale. From an economic perspective, government and state-level services contribute most to Williamson County's overall GDP. Williamson County is Illinois's 65th biggest county (444 square miles). It's located in the Southern Illinois region of the state.