The building was listed on the
National Register of Historic Places in 1988 for its status as a "well-known landmark that is referred to frequently in factual and fictitious contexts" and its "exceptional significance" in the "nation's economic history". The site is located on what is now the intersection of Bullion Boulevard and Gold Vault Road.
Planning and completion In June 1935, the U.S. Treasury announced its intention to quickly build a gold depository on the grounds of Fort Knox,
Kentucky. Its purpose was to store gold then kept in the
New York City Assay Office and the
Philadelphia Mint. This intent was in keeping with a policy previously announced to move gold reserves away from coastal cities to areas less vulnerable to foreign military invasion. This policy had already led to the shipment of nearly of gold from the
San Francisco Mint to the
Denver Mint. The initial plans were to be completed by August and called for a building costing no more than $450,000 (). Cited were several military advantages of the location. An army attacking from the
Eastern Seaboard would have to fight through the
Appalachian Mountains, which were considered a reasonable impediment to military forces of the time. It was also isolated from railways and highways which would further hinder an attacking power. Even air travel to the location across the mountains was considered dangerous for a pilot unfamiliar with the territory. Finally, the Army's only completely mechanized cavalry unit was stationed at the adjacent Fort and could readily be deployed to defend the depository. The gold was transported from the New York Assay Office and the Philadelphia Mint onto trains using
postal trucks and
municipal police escorts. Decoy trains were employed. The Post Office Department billed the Treasury Department for transporting the weight of the crates and gold using the fourth-class postage rate with added insurance fees. It took over five months and required 39 trains consisting of 215 cars. This wave of shipments began in July of the previous year and was also overseen by the Post Office. It took seven months and required 45 trains consisting of 337 cars.
Accumulation of reserves The building and early operation of the depository occurred at the same time total gold reserves in the United States experienced unprecedented growth. These reserves, which were at the end of 1933, jumped to by the end of 1939. Factors driving this growth included the
gold price revaluation (dollar devaluation) in 1934 spurring a rise in global gold production, political uncertainties in Europe causing a
capital flight to the United States, and re-armament programs in Europe which increased U.S.
net merchandise exports. By the end of 1940, total Treasury reserves stored at all locations rose to . This accounted for around 80 percent of the entire world's gold reserves. Total U.S. gold reserves stored at all locations peaked in October 1941 at and ended the year at .
Historic documents and
US Constitution after arriving back to the
Library of Congress in October 1944 after having been stored at Fort Knox
Librarian of Congress Archibald MacLeish expressed concern with the safety of the library's precious artifacts as soon as he took office in 1939. As the
Battle of Britain was fought during the summer and fall of 1940, MacLeish asked the
U.S. Geological Survey about locating underground storage for "valuable paintings and books" and "within reasonable distance of
Washington." In December 1940, he directed his staff to create a detailed catalog of the
Library of Congress's most "irreplaceable" assets, and the space required to store them. Primary attention was given to those items "considered most important for the history of democracy." When it became clear that Congress would not fund the building of a separate facility, Macleish sought other options. On April 30, 1941, he requested of the Treasury Secretary some thousands of cubic feet at Fort Knox for the most notable items in the library. The secretary replied, offering the librarian ten cubic feet. In July, when the inventory was complete, and it had been determined that some 40,000 cubic feet would be required for the storage of all unique and irreplaceable materials of the library, the original ten cubic feet offer was raised to 60.3 cubic feet. MacLeish prioritized items to be sent to Fort Knox. which had been on loan to the United States for the
1939 New York World's Fair. The items were packed in four crates and then shipped by train to the depository on December 26, 1941. An air conditioning unit and calcium chloride
dryers were installed in the vault. Frequent inspections were made. In May 1942, repairs were made to the Declaration. In April 1943, the Declaration and the Constitution were removed from and then taken back to the depository so they could be displayed at the opening of the
Jefferson Memorial. On October 1, 1944, all items were returned to the Library of Congress. The copy of
Magna Carta was returned to England after the war in January 1946.
Other artifacts After
World War II, the depository held the
Crown of St. Stephen, as well as other
Hungarian crown jewels including a gold scepter and orb and a gold‐encrusted mantle. They were given to U.S. military authorities by members of the
Royal Hungarian Crown Guard who feared that they would otherwise fall into
Soviet hands. The items were kept in Germany under U.S. custody for several years before being transferred to Fort Knox. They were returned to Hungary in 1978. In 1955, the
Defense Logistics Agency began storing
opium and
morphine at the depository and the
West Point Mint. This was done to ensure the nation had adequate supplies in case of war or supply disruptions from the limited number of poppy exporters. The stockpile grew to , enough to meet the legal painkiller needs of the entire United States for one year if supplies were cut off. As the
Cold War ended, and more nations began exporting concentrated
poppy straw, concerns about supply disruptions abated. But the agency could not legally sell its opium or morphine stock without congressional approval. So, in 1993, it converted its remaining opium reserves into morphine sulfate. This was done to extend the life of the stock since morphine has a longer shelf-life than opium. Morphine is no longer stored at the depository. ==Construction and security==