The Army Ground Forces were one of the three autonomous components of the Army of the United States during World War II, the others being the Army Air Forces and Army Service Forces. Throughout their existence, Army Ground Forces were the largest training organization ever established in the United States. Its strength of 780,000 troops on 1 May 1942 grew to a peak of 2,200,000 by 1 July 1943. Thereafter its strength declined as units departed for overseas theaters. Origins Army Ground Forces traced their origins back to General Headquarters, United States Army (GHQ), which were activated on 26 July 1940. Although inactive before this date, GHQ had long featured in mobilization plans as far back as 1921 as a headquarters for directing US field armies overseas, similar to that of the American Expeditionary Forces in World War I. This was not realized in practice because the war was fought in many theaters, so overall direction was exercised by the War Department's General Staff. GHQ also did not become the equivalent of a theater command for the Zone of Interior; administrative authority was exercised by the G-4 of the War Department's General Staff through the Corps Areas and Service Commands. Instead, GHQ was drawn into the enormous task of raising and training an army. Nominally, the U.S. Army Chief of Staff, George C. Marshall, was the commanding general of GHQ, while his Chief of Staff was Lieutenant General Lesley J. McNair, who had been Commandant of the Command and General Staff School. However, since Marshall saw him infrequently and seldom visited GHQ (located at the Army War College), it was in practice McNair who directed GHQ. In March 1942, there was a sweeping reorganization of the Army that reduced the number of officers reporting to the chief of staff. Under Executive Order 9082 "Reorganizing the Army and the War Department" of 28 February 1942 and War Department Circular No. 59 of 2 March 1942, GHQ became Headquarters, Army Ground Forces, and opened at the Army War College on 9 March 1942. The posts of the chiefs of the four traditional combat arms – Infantry, Cavalry, Field Artillery, and Coast Artillery – were abolished and their functions, duties, and powers were transferred to the Army Ground Forces. McNair also became responsible for four new 'pseudo-arms' – airborne, armor, anti-aircraft and tank destroyer. He had the power to reorganize the ground army,