There are 7 US Post Offices in Hancock County serving a total of 10,154 residents equating to 1,451 residents per post office. It's estimated that approximately 16,207 packages are handled across the 7 county post offices annually. Hancock County is a county located in the U.S. state of Iowa. As of the 2010 census, the population was 11,341. The county seat is Garner. The county was founded on January 15, 1851 and named in honor of John Hancock, a leader of the Continental Congress during the American Revolution."