The combined value of farms, hunting land and other rural land and acreage for sale in Mason County recently on Land.com was around $5 million. This represents 1,000 acres of land and rural real estate for sale in Mason County. Mason County ranks 88th out of 102 counties in the Prairie State for the total number of acres of land currently advertised for sale. Of all locations in Mason County with land and rural real estate for sale, Forest City featured the most land for sale. Mason County is the 47th largest county (563 square miles) in Illinois. It's located in the Western Illinois region of Illinois.