Land for sale in Grant County, South Dakota, recently totaled approximately $5 million and almost 1,000 acres. Grant County ranks 36th out of 66 counties in the state for the total acreage of land currently advertised for sale. Of all locations in Grant County with farms, ranches, hunting land and other land for sale, Milbank featured the most land for sale. Grant County is the 48th largest county (687 square miles) in South Dakota. It's located in the Glacial Lakes & Prairies South Dakota region of South Dakota.