The value of land and rural real estate for sale in Illinois's Piatt County recently on Land.com was $6 million. This represents around 1,000 acres of land for sale in Piatt County. Piatt County ranks 79th out of 102 counties in Illinois for the combined amount of land currently advertised for sale. Monticello had the most land for sale. Its economy is defined as agricultural, with 426 farms recorded in the county during the most recent U.S. Census. Farming activities in Piatt County generate annual revenues of $18 million, most of which is from crops. Piatt County is the 67th biggest county (439 square miles) in Illinois. It's located in the Central Illinois region of the state.