There are 6 US Post Offices in Kay County serving a total of 36,916 residents equating to 6,153 residents per post office. It's estimated that approximately 58,922 packages are handled across the 6 county post offices annually. Kay County is a county located in the U.S. state of Oklahoma. As of the 2010 census, the population was 46,562. Its county seat is Newkirk, and the largest city is Ponca City. Kay County comprises the Ponca City, OK Micropolitan Statistical Area. It is in north central Oklahoma on the Kansas state line. Before statehood, Kay County was formed from the \u201cCherokee Strip\u201d or \u201cCherokee Outlet\u201d and originally designated as county \u201cK.\u201d Its name means simply that. Kay County is the only county to keep its same name as the Oklahoma area moved from a territory to a state."