There are 23 US Post Offices in Sedgwick County serving a total of 225,832 residents equating to 9,819 residents per post office. It's estimated that approximately 360,453 packages are handled across the 23 county post offices annually. Sedgwick County (standard abbreviation: SG) is a county located in the U.S. state of Kansas. As of the 2010 census, the population was 498,365, making it the second-most populous county in Kansas. The county seat is Wichita, the most populous city in the state."