Land for sale in Piatt County recently totaled approximately $6 million and almost 1,000 acres. Piatt County ranks 80th in Illinois for the total acreage of land currently advertised for sale. Of all locations in Piatt County with land for sale, Mansfield had the most land for sale. Piatt County has a large agricultural economy, with 426 farms recorded in the county during the latest 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 largest county (439 square miles) in Illinois. It's located in the Central Illinois region of the state.