Sanborn County ranks 60th out of 66 counties in the Mount Rushmore State for the total number of acres of land currently advertised for sale. Among cities in Sanborn County with land for sale, Letcher had the most land for sale. Its economy is defined as agricultural, with 402 farms recorded in the county during the most recent U.S. Census. Farming activities in Sanborn County generate annual revenues of $12 million, most of which is from crops. Sanborn County is the 56th largest county (570 square miles) in South Dakota. It's located in the Glacial Lakes & Prairies South Dakota region of the state.