There are 4 US Post Offices in Dawson County serving a total of 8,954 residents equating to 2,239 residents per post office. It's estimated that approximately 14,292 packages are handled across the 4 county post offices annually. Dawson County is a county located in the U.S. state of Montana. As of the 2010 census, the population was 8,966. Its county seat is Glendive."