When was the Portsmouth Naval Yard judged to be within the state of Maine?
Piscataqua River border dispute: The Piscataqua River border dispute was a dispute between the US states of Maine and New Hampshire over ownership of Seavey’s Island in the Piscataqua River, which forms the border between Maine and New Hampshire. Piscataqua River border dispute:  The dispute was settled in 2002 by the US Supreme Court in favor of Maine. Seavey's Island: Seavey's Island, on which the Portsmouth Naval Shipyard resides, is located in the Piscataqua River in Kittery, Maine, opposite Portsmouth, New Hampshire.
2002