Land for sale in Union County, Indiana, recently totaled $4 million and nearly 1,000 acres. Union County ranks 92nd in Indiana for the total number of acres of land currently advertised for sale. Among cities in Union County with farms, rural land, hunting land and other land for sale, Liberty featured the most land for sale. Union County is the 90th largest county (165 square miles) in Indiana. It's located in the East Indiana region of the state.