There are 7 US Post Offices in York County serving a total of 13,770 residents equating to 1,967 residents per post office. It's estimated that approximately 21,978 packages are handled across the 7 county post offices annually. York County is a county in the U.S. state of Nebraska. As of the 2010 census, the population was 13,665. Its county seat is York. In the Nebraska license plate system, York County is represented by the prefix 17 (it had the seventeenth-largest number of vehicles registered in the county when the license plate system was established in 1922)."