A total of nearly 1,000 acres were listed for sale in Mason County recently, representing a total value of nearly $4 million in Mason County farmsand rural real estate for sale. Mason County ranks 89th out of 102 counties in the Prairie State for the combined amount of land currently advertised for sale. Of all farms and rural real estate for sale in Mason County, Manito had 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.