There are 4 US Post Offices in Wheatland County serving a total of 2,100 residents equating to 525 residents per post office. It's estimated that approximately 3,352 packages are handled across the 4 county post offices annually. Wheatland County is a county located in the U.S. state of Montana. As of the 2010 census, the population was 2,168. Its county seat is Harlowton."