Question: When was the Portsmouth Naval Yard judged to be within the state of Maine?

Context articles: Seavey's Island
HMNB Portsmouth
Harbor Defenses of Portsmouth
Portsmouth Naval Prison
Arnold Kramish
Portsmouth Naval Shipyard Museum
Piscataqua River border dispute
Portsmouth Naval Shipyard
HMS Halifax (1806)
Portsmouth Historic Dockyard

Seavey's Island, on which the Portsmouth Naval Shipyard resides, is located in the Piscataqua River in Kittery, Maine, opposite Portsmouth, New Hampshire.
 It encompasses 278 acre .
Her Majesty's Naval Base, Portsmouth (HMNB Portsmouth) is one of three operating bases in the United Kingdom for the British Royal Navy (the others being HMNB Clyde and HMNB Devonport).
 Portsmouth Naval Base is part of the city of Portsmouth; it is located on the eastern shore of Portsmouth Harbour, north of the Solent and the Isle of Wight.
 Until the early 1970s it was officially known as Portsmouth Royal Dockyard (or HM Dockyard, Portsmouth); the shipbuilding, repair and maintenance element of the base was privatized in the late-1990s/early-2000s.
The Harbor Defenses of Portsmouth was a United States Army Coast Artillery Corps harbor defense command.
 It coordinated the coast defenses of Portsmouth, New Hampshire and the nearby Portsmouth Naval Shipyard in Kittery, Maine from 1900 to 1950, both on the Piscataqua River, beginning with the Endicott program.
 These included both coast artillery forts and underwater minefields.
 The command originated circa 1900 as the Portsmouth Artillery District, was renamed Coast Defenses of Portsmouth in 1913, and again renamed Harbor Defenses of Portsmouth in 1925.
Portsmouth Naval Prison is a former U.S. Navy and Marine Corps prison on the grounds of the Portsmouth Naval Shipyard (PNS) in Kittery, Maine.
 The building has the appearance of a castle.
 The reinforced concrete naval prison was occupied from 1908 until 1974.
Arnold Kramish (June 6, 1923 – June 15, 2010) was an American nuclear physicist and author who was associated with the Manhattan Project.
 While working on the project, he was nearly killed in an accident at the Philadelphia Naval Yard where a prototype thermal diffusion isotope separation device was being constructed.
 The priest of the Philadelphia Naval Yard offered last rites to Kramish, who refused, as he was Jewish.
 After World War II, he wrote numerous books on nuclear issues.
 He is perhaps best known for his book "The Griffin - the greatest untold espionage story of World War II", about Paul Rosbaud, who passed important scientific and military information from Germany to the Allies.
The Portsmouth Naval Shipyard Museum and the associated Lightship Museum are located on the downtown Portsmouth, Virginia, United States waterfront.
 The museum covers the 250+ year relationship with the shipyard - America's oldest and largest naval shipyard located on the Portsmouth Waterfront.
 The city and the shipyard have been intertwined since the founding of the Gosport Shipyard in 1767, which was later renamed Norfolk Navy Yard and finally Norfolk Naval Shipyard.
 This rich history is told through exhibits, hands-on programs and special events.
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.
 The dispute was settled in 2002 by the US Supreme Court in favor of Maine.
The Portsmouth Naval Shipyard (PNS), often called the Portsmouth Navy Yard, is a United States Navy shipyard located in Kittery on the southern boundary of Maine near the city of Portsmouth, New Hampshire.
 PNS is tasked with the overhaul, repair, and modernization of US Navy submarines.
 The facility is sometimes confused with the Norfolk Naval Shipyard in Portsmouth, Virginia.
HMS "Halifax" was a ship-rigged sloop of the "Merlin" class built in 1806 for the British Royal Navy at the Naval Yard in Halifax, Nova Scotia.
 Built to fill a pressing need for coastal patrol sloops on the North American Station, "Halifax" was one of the few warships built at Halifax Naval Yard in the Age of Sail as the yard's primary function was supply and refit.
Portsmouth Historic Dockyard is an area of HM Naval Base Portsmouth which is open to the public; it contains several historic buildings and ships.
 It is managed by the National Museum of the Royal Navy as an umbrella organisation representing five charities: the Portsmouth Naval Base Property Trust, the National Museum of the Royal Navy Portsmouth, the Mary Rose Trust, the "Warrior" Preservation Trust Ltd and the HMS "Victory" Preservation Company.
 Portsmouth Historic Dockyard Ltd was created to promote and manage the tourism element of the Royal Navy Dockyard, with the relevant trusts maintaining and interpreting their own attractions.
 It also promotes other nearby navy-related tourist attractions.