Land for sale in Mercer County recently totaled almost $19 million and around 3,000 acres. Mercer County ranks 97th in the Gateway State for the total acreage of land currently advertised for sale. Of all locations in Mercer County with farms, ranches, and rural real estate for sale, Princeton featured the most land for sale. Agriculture and farming drives the Mercer County economy, with 567 farms recorded in the county during the U.S. Census in 2012. Farming activities in Mercer County generate annual revenues of $5 million, the majority of which comes from livestock products. Mercer County is the 95th largest county (455 square miles) in Missouri. It's located in the Northwest Missouri region of the state.