The value of all farmsand rural real estate for sale in Washington County recently was nearly $4 million, representing a total of 64 acres of land for sale in Washington County. Washington County ranks 75th in Illinois for the total number of acres of land currently advertised for sale. Of all locations in Washington County with farms, rural land, hunting land and other land for sale, Nashville featured the most land for sale. Washington County is the 46th biggest county (563 square miles) in Illinois. It's located in the Southern Illinois region of Illinois.