There are 2 US Post Offices in Mcduffie County serving a total of 21,816 residents equating to 10,908 residents per post office. It's estimated that approximately 34,821 packages are handled across the 2 county post offices annually. McDuffie County is a county located in the U.S. state of Georgia. As of the 2010 census, the population was 21,875. The county seat is Thomson. The county was created on October 18, 1870 and named after the South Carolina governor and senator George McDuffie. McDuffie County is part of the Augusta-Richmond County, GA-SC Metropolitan Statistical Area."