There are 40 US Post Offices in York County serving a total of 215,201 residents equating to 5,380 residents per post office. It's estimated that approximately 343,485 packages are handled across the 40 county post offices annually. York County is the most southwestern county of the state of Maine located along New Hampshire's eastern border in the United States. It is divided from Strafford County, New Hampshire by the Salmon Falls River, and the connected tidal estuary\u2014the Piscataqua River. Permanently re-founded in 1639, it held several of the oldest colonial settlement in Maine; consequently, is the oldest county in Maine and one of the oldest in the United States. As of the 2010 census, the population was 197,131, making it the second-most populous county in Maine. Its county seat is Alfred. York County is part of the Portland\u2013South Portland, ME Metropolitan Statistical Area."