There are 2 US Post Offices in Haskell County serving a total of 4,020 residents equating to 2,010 residents per post office. It's estimated that approximately 6,416 packages are handled across the 2 county post offices annually. Haskell County (county code HS) is a county located in the U.S. state of Kansas. As of the 2010 census, the county population was 4,256. Its county seat and most populous city is Sublette."