There are 2 US Post Offices in Treasure County serving a total of 758 residents equating to 379 residents per post office. It's estimated that approximately 1,210 packages are handled across the 2 county post offices annually. Treasure County is a county located in the U.S. state of Montana. As of the 2010 census, the population was 718, making it the second-least populous county in Montana. Its county seat is Hysham. The county was founded in 1919."