The value of all farmsand rural real estate for sale in Illinois's Washington County recently was around $2 million, representing a total of 206 acres of land for sale in Washington County. Washington County ranks 75th in the Land of Lincoln for the total acreage of land currently advertised for sale. Ashley had the most land for sale. Washington County is Illinois's 46th biggest county (563 square miles). It's located in the Southern Illinois region of Illinois.