There are 3 US Post Offices in Houston County serving a total of 8,280 residents equating to 2,760 residents per post office. It's estimated that approximately 13,216 packages are handled across the 3 county post offices annually. Houston County is a county located in the U.S. state of Tennessee. As of the 2010 census, the population was 8,426. Its county seat is Erin. The county was founded in 1871. It was named for Sam Houston."