Interwar period Sixth Army (I) The first iteration of the Sixth Army was authorized by the
National Defense Act of 1920 and was originally to be composed of
Organized Reserve units primarily from the Seventh, Eighth, and Ninth
Corps Areas. The Sixth Army Headquarters and Headquarters Company were constituted in the Organized Reserve on 15 October 1921 and allotted to the Seventh Corps Area.
Little Rock,
Arkansas, was designated as the army headquarters upon organization, but the unit was never organized at that location. The Headquarters Company was initiated 13 October 1922 at Little Rock. Little Rock remained the Sixth Army’s headquarters location upon the event of its activation until 25 February 1924, when
St. Louis,
Missouri, was designated as the army’s new headquarters location. The headquarters was initiated in August 1924 at St. Louis. The Headquarters Company was inactivated at Little Rock on 1 October 1924 and relocated to St. Louis. Due to the abandonment of the “Six Army” plan in favor of the “Four Army” plan, the Sixth Army was deleted from the mobilization plans on 1 October 1933 and demobilized (disbanded). Its subordinate units were reassigned to the Fourth Army, the General Headquarters Reserve, or demobilized.
World War II Sixth Army (II) The Sixth United States Army was activated in January 1943, commanded by Lieutenant General
Walter Krueger. Under the code name
Alamo Force, it assumed control of the majority of
US Army units involved in
Operation Cartwheel, the campaign to isolate and neutralize the Japanese base at
Rabaul in
New Britain. Following the completion of Cartwheel, Sixth Army joined the
Australian Army and other US forces on the north coast of
New Guinea. Similar in conception to the island hopping operations of the central Pacific, the object of the attacks was to land, establish a garrison and airfield which could support the next strike, and then move on. In September 1944, Sixth Army was relieved from operations in New Guinea by the
Eighth Army. On 20 October 1944,
X Corps and
XXIV Corps, under Sixth Army, invaded
Leyte in the
Philippines. By December, Leyte was secured, and the Sixth Army was relieved again by Eighth Army to prepare for the invasion of
Luzon. As a prelude to that invasion, the island of
Mindoro was invaded by the
Western Visayan Task Force comprising the
19th and
503rd Regimental Combat Teams. Sixth Army took part in the
Invasion of Lingayen Gulf on 9 January 1945 with the subordinate units of
I and
XIV Corps. Sixth Army units fought south until they met up those of Eighth Army advancing from around
Manila. Sixth Army then continued to clear the north of Luzon and confronted the
Shimbu Group in the
Sierra Madres until the end of the war. Sixth Army was to have provided the ground forces for the first phase of the
invasion of Japan, though after
Japan's early surrender Sixth Army was reassigned to
occupation duty in Japan. Sixth Army returned to the United States in 1946, and was headquartered at the
Presidio of San Francisco. After the war, Sixth Army took responsibility for training of Army forces from part of the continental United States. It was eventually inactivated in June 1995 due to force reductions. ==Reactivation==