There are 7 US Post Offices in Barton County serving a total of 27,945 residents equating to 3,992 residents per post office. It's estimated that approximately 44,603 packages are handled across the 7 county post offices annually. Barton County (standard abbreviation: BT) is a county located in the U.S. state of Kansas. As of the 2010 census, the county population was 27,674. Its county seat and most populous city is Great Bend. The county is named in honor of Clara Barton, responsible for the founding of the American Red Cross.