There are 3 US Post Offices in Mineral County serving a total of 4,613 residents equating to 1,538 residents per post office. It's estimated that approximately 7,363 packages are handled across the 3 county post offices annually. Mineral County is a county located in the U.S. state of Montana. As of the 2010 census, the population was 4,223. Its county seat is Superior."