There are 4 US Post Offices in Harding County serving a total of 815 residents equating to 204 residents per post office. It's estimated that approximately 1,301 packages are handled across the 4 county post offices annually. Harding County is a county located in the U.S. state of South Dakota. As of the 2010 census, the population was 1,255, making it the second-least populous county in South Dakota. Its county seat is Buffalo. The county was established in 1881 and named in honor of J.A. Harding, who had been Speaker of the House of the Dakota Territory. It was merged for a few years with Butte County, under that county's name, but became separate again in 1909. Custer National Forest has its South Dakota portion in Harding County, and South Dakota State University operates the Antelope Range and Livestock Research Station about 14 miles (23 km) east of Buffalo."