Fort Knox is named after General Henry Knox, Chief of Artillery in the Continental Army, and the first US Secretary of War. The modern fort was established in 1918 as Camp Knox, a recruit training camp for soldiers being deployed to Europe in World War I. Before Fort Knox, Fort Duffield, a Union post in the Civil War, had been sited nearby.


The area of West Point and land from Hardin, Bullitt and Meade counties intended to establish a permanent artillery training camp at Camp Knox, but the end of the war led to a reduction of funding and the camp was deactivated. It was kept on as a training center for the 5th Corps Area, the National Guard, and Citizen's Military Training Camps (CMTC).


In early 1932 Camp Knox was selected to be the home of the Mechanized Cavalry. The camp was made a permanent military installation and renamed Fort Knox. Soon after, the Army's oldest mounted unit, the 1st Cavalry Regiment, traded in their horses for armored combat cars. Four years later, the 13th Cavalry Regiment joined the 1st Cavalry Regiment to become the 7th Cavalry Brigade (later renamed the 1st Armored Division). The fort became critical in the early US doctrine of armored warfare. Just before the US entry into World War II, the Armored Replacement Training Center (ARTC) and the Armored Force School were established at Fort Knox.


With the entrance of WWII, Fort Knox saw a variety of events and changes. Technological advancements in armor lead to the development of new tanks and training. The fort was also the site of a prisoner of war camp housing Italian and German soldiers. POWs had normal camp lives, including work details and recreational activities. It wasn't uncommon for POWs to form friendships with the civilians they worked with. To this day, there are 18 prisoners buried in the post cemetery.


From the 1950's to present, Fort Knox continued to build its reputation in armor and cavalry development. The armor and cavalry were merged to form the Armor Branch, the Armored Replacement Training Center was renamed the U.S Army Training Center, Armor, and the Armor Center and School became the Army Armor Center. By the end of the 1960s, over one million trainees had completed a program at Fort Knox.


During the 1980's, the fort's research played a major role in the development of the Army's AirLand Battle doctrine, which was implemented successfully during the Gulf War in the nineties. However, in 2005, as a result of the BRAC commission, the Armor Center and School, and the Armor School were relocated to Fort Benning. Also relocated to Fort Knox were the Human Resources Command, Army Accessions Command and Cadet Command, as well as units such as the 3rd Brigade Combat Team, 1st Infantry Division; Army Reserve Readiness Training Center; 100th Division Headquarters; and the 3rd Sustainment Command (Expeditionary). Today, Fort Knox is home to the Army's Human Resource Center of Excellence, and continues to play an integral role in the development and training of military installations.