There are 7 US Post Offices in Franklin County serving a total of 11,543 residents equating to 1,649 residents per post office. It's estimated that approximately 18,424 packages are handled across the 7 county post offices annually. Franklin County is a county located in the U.S. state of Iowa. As of the 2010 census, the population was 10,680. The county seat is Hampton. The county was formed on January 15, 1851 and named after Benjamin Franklin."