There are 5 US Post Offices in Stark County serving a total of 4,942 residents equating to 988 residents per post office. It's estimated that approximately 7,888 packages are handled across the 5 county post offices annually. Stark County is a county located in the U.S. state of Illinois. According to the 2010 census, it had a population of 5,994. Its county seat is Toulon. Stark County is part of the Peoria, IL Metropolitan Statistical Area."