Rock Island County
There are 17 US Post Offices in Rock Island County serving a total of 147,695 residents equating to 8,688 residents per post office. It's estimated that approximately 235,738 packages are handled across the 17 county post offices annually. Rock Island County is a county located in the U.S. state of Illinois, bounded on the west by the Mississippi River. According to the 2010 census, it had a population of 147,546. Its county seat is Rock Island; its largest city is neighboring Moline. Rock Island County is one of the four counties that make up the Davenport-Moline-Rock Island, IA-IL Metropolitan Statistical Area."