The Fourth United States Army was organized as Fourth Army in the Organized Reserves in 1922 at New York City, NY. It was withdrawn from the Organized Reserves on 9 August 1932 and allotted to the Regular Army as an inactive unit. It was activated 1 October 1933 and headquartered at the Presidio of San Francisco, California. It was redesignated Fourth United States Army on 1 January 1957.
The Fourth United States Army has no combat record. It remained in the Continental United States during World War II, training tactical units to operate efficiently in combat. In addition, Fourth Army was largely responsible for the defense of the West Coast.