Historical Fort Mckinley and Great Diamond Island
Fort McKinley was constructed by the U.S. Army's Coast Artillery Corps on the northern half of Great Diamond Island as part of the national coastal defense system. Construction began in 1890 with installation of facilities to mine the Hussey Sound entrance to Portland Harbor. The first large gun battery was completed in 1897, with a total of 9 batteries housing 26 total guns in place by 1905. The fort was officially named after President William McKinley shortly after he was assassinated in 1901.
Fort McKinley was active during the Spanish-American War (1898), World War I (1917-1918), and World War II (1941-1945). Between the world wars the 5th Infantry Regiment was stationed at the fort and a Citizen's Military Training Camp (CMTC) operated each summer to provide young men an introduction to military life.
During WWII, the U.S. Navy built a Naval Training Center on the north fork of the island.
The fort was typically staffed with 800 troops, swelling to some 1400 during WW II. Most were housed in barracks plus NCO and officer's houses within the fort, though some were billeted in private cottages on the other side of the island which pre-dated the fort's construction.
The fort was abandoned by the U.S. Army in 1947, administration passed to the U.S. Navy in 1954, and the property was sold to private owners in 1961. The property fell into disrepair. In 1984 the property was purchased for development and the former fort area was listed on the National Register of Historic Places. Most of the fort's buildings have now been restored and converted to private residences that make up the Diamond Cove community.
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