There are 14 US Post Offices in Henry County serving a total of 49,109 residents equating to 3,508 residents per post office. It's estimated that approximately 78,383 packages are handled across the 14 county post offices annually. Henry County is a county located in the U.S. state of Illinois. According to the 2010 census, it has a population of 50,486. Its county seat is Cambridge. Henry County is included in the Davenport-Moline-Rock Island, IA-IL Metropolitan Statistical Area."