There are 6 US Post Offices in Montgomery County serving a total of 160,363 residents equating to 26,727 residents per post office. It's estimated that approximately 255,957 packages are handled across the 6 county post offices annually. Montgomery County is a county located in the U.S. state of Tennessee. As of the 2010 census, the population was 172,331. The county seat is Clarksville. The county was created in 1836. Montgomery County is included in the Clarksville, TN\u2013KY Metropolitan Statistical Area."