There are 4 US Post Offices in Scott County serving a total of 4,854 residents equating to 1,214 residents per post office. It's estimated that approximately 7,748 packages are handled across the 4 county post offices annually. Scott County is a county located in the U.S. state of Illinois. According to the 2010 census, it had a population of 5,355, making it the fourth-least populous county in Illinois. Its county seat is Winchester. Scott County is part of the Jacksonville, IL Micropolitan Statistical Area, which is also included in the Springfield-Jacksonville-Lincoln, IL Combined Statistical Area."