Oldest Operating Post In America | Hinsdale Post Office (est. 1816): Hinsdale, NH
From the article: "...The oldest post office in America is Hinsdale, New Hampshire Post Office. It is recognized as the oldest Post office by the United States Postal Service (USPS). The Historical Marker Database acknowledges it as the Nation's oldest continuously operating post office building. The town of Hinsdale, NH defines it as the oldest continuously operating post office.
The Hinsdale, New Hampshire post office has a rich history, dating back to 1816. In 1815..."
Article Reference: historictownsofamerica.com/