There are 8 US Post Offices in Cowley County serving a total of 36,225 residents equating to 4,528 residents per post office. It's estimated that approximately 57,819 packages are handled across the 8 county post offices annually. Cowley County (county code CL) is a county located in the U.S. state of Kansas. As of the 2010 census, the county population was 36,311. Its county seat is Winfield, and its most populous city is Arkansas City."