There are 6 US Post Offices in Anderson County serving a total of 8,253 residents equating to 1,376 residents per post office. It's estimated that approximately 13,173 packages are handled across the 6 county post offices annually. Anderson County (county code AN) is a county located in East Central Kansas, in the Central United States. As of the 2010 census, the county population was 8,102. Its county seat and most populous city is Garnett."