There are 7 US Post Offices in Republic County serving a total of 4,637 residents equating to 662 residents per post office. It's estimated that approximately 7,401 packages are handled across the 7 county post offices annually. Republic County (standard abbreviation: RP) is a county located in the state of Kansas. As of the 2010 census, the county population was 4,980. The largest city and county seat is Belleville. It is south from the Nebraska state line."