There are 6 US Post Offices in Marlboro County serving a total of 28,830 residents equating to 4,805 residents per post office. It's estimated that approximately 46,016 packages are handled across the 6 county post offices annually. Marlboro County is a county located in the U.S. state of South Carolina. As of the 2010 census recorded its population to be 28,933. Its county seat is Bennettsville. The Great Pee Dee River runs through it. Marlboro County comprises the Bennettsville, SC Micropolitan Statistical Area. Among its residents are the state-recognized Pee Dee Tribe of South Carolina (2006) and the Pee Dee Indian Nation of Upper South Carolina (2005). The first is based in McColl as is the Marlboro, Chesterfield, Darlington County Pee Dee Indian Tribe, which separated from the second listed Pee Dee tribe. Nearly 5% of the county population identify as Pee Dee people."