There are 8 US Post Offices in Robertson County serving a total of 69,347 residents equating to 8,668 residents per post office. It's estimated that approximately 110,686 packages are handled across the 8 county post offices annually. Robertson County is a county located in the U.S. state of Tennessee. As of the 2010 census, the population was 66,283. Its county seat is Springfield. The county was named for James Robertson, founder of Nashville and a state senator. Robertson County is a component of the Nashville-Davidson\u2013Murfreesboro\u2013Franklin, TN Metropolitan Statistical Area."