There are 30 US Post Offices in Spartanburg County serving a total of 210,935 residents equating to 7,031 residents per post office. It's estimated that approximately 336,676 packages are handled across the 30 county post offices annually. Spartanburg County is a county located in the U.S. state of South Carolina. The 2015 population estimate is 297,302, making it the fourth-most populous county in South Carolina. Its county seat is Spartanburg. Spartanburg County is included in the Spartanburg, SC Metropolitan Statistical Area, which is also included in the Greenville\u2013Spartanburg\u2013Anderson, SC Combined Statistical Area. The USS Spartanburg County (LST-1192) is named after the county."