The Piscataqua River is a tidal estuary located in the northeastern United States, primarily forming the border between New Hampshire and Maine. It flows into the Atlantic Ocean and is known for its strong currents and deep waters, making it a significant waterway for shipping and recreation. The river is approximately 12 miles long and is fed by several tributaries, including the Salmon Falls River and the Cocheco River. The surrounding area features historic towns like Portsmouth, New Hampshire, which has a rich maritime history and is a popular destination for tourists and boaters.