Land for sale in Montana's Musselshell County recently totaled approximately $76 million and around 100,000 acres. Musselshell County ranks 20th based on the total acres of land for sale of the 56 counties in Montana. Among cities in Musselshell County with ranches, farms, hunting land and other rural land and acreage for sale, Roundup had the most land for sale. Mining and mineral extraction-related services are the main economic drivers in this part of Montana. Musselshell County is the 35th biggest county (1,871 square miles) in Montana. It's located in the Southeast Montana region of the state.