There are 5 US Post Offices in Chautauqua County serving a total of 3,416 residents equating to 683 residents per post office. It's estimated that approximately 5,452 packages are handled across the 5 county post offices annually. Chautauqua County (county code CQ) is a county located in Southeast Kansas. As of the 2010 census, the county population was 3,669. Its county seat and most populous city is Sedan. Chautauqua County is named for Chautauqua County, New York, the birthplace of Edward Jaquins, a Kansas politician who was instrumental in getting the county established."