Land for sale in Roberts County, South Dakota, recently totaled approximately $9 million and nearly 1,000 acres. Roberts County ranks 13th in the Mount Rushmore State for the total acreage of land currently advertised for sale. Of all farms and ranches for sale in Roberts County, Big Stone City had the most land for sale. Roberts County has a large agricultural economy, with 876 farms recorded in the county during the latest U.S. Census. Farming activities in Roberts County generate annual revenues of $16 million, most of which is from crops. Roberts County is South Dakota's 27th largest county (1,135 square miles). It's located in the Glacial Lakes & Prairies South Dakota region of South Dakota.