There are 3 US Post Offices in Brantley County serving a total of 11,519 residents equating to 3,840 residents per post office. It's estimated that approximately 18,386 packages are handled across the 3 county post offices annually. Brantley County is a county located in the U.S. state of Georgia. As of the 2010 census, the population was 18,411. The county seat is Nahunta. Brantley County is part of the Brunswick, GA Metropolitan Statistical Area."