There are 8 US Post Offices in Sumter County serving a total of 64,838 residents equating to 8,105 residents per post office. It's estimated that approximately 103,489 packages are handled across the 8 county post offices annually. Sumter County is a county located in the U.S. state of South Carolina. As of the 2010 census, the population was 107,456; in a 2013 census estimate, the population was at 108,123. Its county seat is Sumter. The county was created in 1800. Sumter County comprises the Sumter, South Carolina Metropolitan Statistical Area. It is the home of Shaw AFB, headquarters to the 9th Air Force, AFCENT, United States Army Central, with a number of other tenant units. It is one of largest bases in the USAF's Air Combat Command."