103d Infantry Division History: The Beginning

The 103d Infantry Division Prior to 1942


The National Defense Act of 1920 divided the Army of the United States into three components. The Regular Army comprised the full-time professional element. The second element was the Militia Bureau, which evolved into the Army National Guard.  The Organized Reserve Officer and Enlisted Reserve Corps, later known as the U. S. Army Reserve, made up the Army's third element.


Supporters of the Act argued that Regular peacetime forces was too small to meet wartime needs.  Therefore, the Act depended on easily mobilized citizen-soldiers to supplement the regular army during wartime.


Passed during peacetime, the Act’s primary mission was to train civilians for the Militia and Organized Reserve. The Act stipulated a structure of two National Guard and three Reserve Corps armies. On 6 August 1921, the War Department authorized the formation of the 103d Infantry Division, widely known from its formation as the 'Cactus Division.' 103d Infantry Division become one of the Reserve Corps Divisions.


In mid-1921, the Division was assigned to New Mexico, Arizona, and Colorado. On 8 September 1921, the 103d Infantry Division established headquarters in Denver, Colorado and Major James A. McGrath assumed command the following day. Lieutenant Colonel Homer Washburn became first Reserve officer and the first commander of the 411th Infantry Regiment.


The structure of the 103d Infantry Division is listed below, by state:



Headquarters, 103d Infantry Division, Denver

Special Division Troops, Denver

Headquarters, 328th Medical Regiment, Denver

206th Infantry Brigade, Denver

411th Infantry Regiment, Denver

412th Infantry Regiment, Denver

178th Field Artillery Brigade, Denver

383d Field Artillery, Denver

328th Engineer Regiment, Golden

103d Division Air Service, Colorado Springs



205th Infantry Brigade, Warren

409th Infantry Regiment, Tucson

382d Field Artillery (Regiment), Prescott

Sanitation Battalion, 328th Medical Regiment, Phoenix



410th Infantry Regiment, Roswell

Ambulance Battalion, 328th Medical Regiment, Las Vegas


By the end of 1922, the 103d Infantry Division had 829 Reserve officers and 50 Reserve enlisted personnel. The "Rocky Mountain Division" adopted the green Saguara Cactus--depicted as growing cactus in blue earth with a yellow sky background--as their symbol. The Division took this shoulder insignia into battle during World War II. In 1923, the division’s name became the "The Cactus Division.” The name remains unchanged.


Pre-World War II, the Army used a square division structure, with four infantry regiments, two brigades, three field artillery regiments, an engineer regiment, Air Service, and special troops. Just prior to World War II, the Army adopted the triangular division structure with three infantry regiments. The 103d Infantry Division also employed this triangular structure, which it used through World War II.

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