A total of 1,000 acres were listed for sale in Mason County recently; the overall value of all Mason County land for sale was approximately $5 million. Mason County ranks 95th in the Inland Empire for the total number of acres of land currently advertised for sale. Among cities in Mason County with land for sale, Forest City featured the most land for sale. Mason County is Illinois's 47th largest county (563 square miles). It's located in the Western Illinois region of the state.