There was a total of around $39 million of farms, ranches, and rural real estate for sale in Madison County recently on Land.com. The total size of all Madison County farms, ranches, and rural real estate for sale was approximately 3,000 acres. Madison County ranks 39th in the Gem State for the total number of acres of land currently advertised for sale. Among cities in Madison County with farms, ranches, and rural real estate for sale, Rexburg had the most land for sale. Madison County is Idaho's 42nd largest county (473 square miles). It's located in the Eastern Idaho region of the state.