There are 5 US Post Offices in Jefferson County serving a total of 53,147 residents equating to 10,629 residents per post office. It's estimated that approximately 84,829 packages are handled across the 5 county post offices annually. Jefferson County is a county located in the U.S. state of Tennessee. As of the 2010 census, the population was 51,407. Its county seat is Dandridge. Jefferson County is part of the Morristown, TN Metropolitan Statistical Area as well as the Knoxville-Morristown-Sevierville, TN Combined Statistical Area.