The value of all farms, ranches, and rural real estate for sale in Union County recently was $23 million, representing a combined 737 acres of land for sale in Union County. Union County ranks 11th out of 66 counties in the Mount Rushmore State for the combined amount of land currently advertised for sale. There were four properties listed as sold in Union County through the Land Network Comparable Sales Program. This represented a total value of $2,080,715. Of all locations in Union County with land for sale, Dakota Dunes featured the most land for sale. Union County is the 62nd biggest county (467 square miles) in South Dakota. It's located in the Southeast South Dakota region of South Dakota.