There are 2 US Post Offices in Jones County serving a total of 866 residents equating to 433 residents per post office. It's estimated that approximately 1,382 packages are handled across the 2 county post offices annually. Jones County is a county located in the U.S. state of South Dakota. As of the 2010 census, the population was 1,006, making it the least populous county in South Dakota. Its county seat is Murdo. Created in 1916 and organized in 1917, it is the most recently established county in South Dakota."