There are 4 US Post Offices in Stafford County serving a total of 4,258 residents equating to 1,065 residents per post office. It's estimated that approximately 6,796 packages are handled across the 4 county post offices annually. Stafford County (standard abbreviation: SF) is a county located in the U.S. state of Kansas. As of the 2010 census, the county population was 4,437. Its county seat is St. John. The county is named in honor of Lewis Stafford, captain of Company E, First Kansas Infantry, who was killed at the Battle of Young's Point, Madison Parrish, Louisiana, June 7, 1863."