Piscataqua River border dispute

Seavey's Island lies in the northern side of the Piscataqua River, between the town of Kittery, Maine, and the city of Portsmouth, New Hampshire.

[3][4] In March 2000, New Hampshire filed a lawsuit in the Supreme Court against Maine, claiming ownership of the island.

[6] The settlement was based on a 1740 decree by King George II, defining the border between the states as the middle of the main navigation channel.

[7][8] Maine responded to the 2001 suit with a request to dismiss based on the principle of res judicata, arguing that the 1740 decision and the outcome of the 1977 case barred New Hampshire from filing another border complaint.

[3]) Justice Ginsburg wrote that "judicial estoppel bars New Hampshire from asserting that the Piscataqua River boundary runs along the Maine shore".

The resolution would need to pass both houses of the state legislature and then be signed by the governor of New Hampshire in order to be adopted.

1893 U. S. Geological Survey map of the area of interest
An aerial view of the Portsmouth Naval Shipyard from the 1930s. The photo is taken from the Maine side—land visible at the top-right of the photo is in New Hampshire.