Basic Elements

The entire army was divided into three basic elements: Army Ground Forces (basic combat units), Army Service Forces (logistical and support troops) and Army Air Forces (flying elements and their support troops). Those units not subordinate to some other headquarters, having an approved shoulder sleeve insignia, would wear the patch of these parent elements. It is very common to see patches of Army Service Forces and Army Air Forces on period uniforms. That of Army Ground Forces and its subordinate General Headquarters Reserves are less commonly seen as most Army Ground Forces units were part of a subordinate element that had its own approved patch.

A Private First Class wearing an Army Service Forces Patch
His branch insignia is Coast Artillery (used also by Antiaircraft Artillery).

Army Ground Forces 1922 (1)	General HQ Reserves 1941 (2)	Army Service Forces 1941	Army Air Forces 1942

Army Groups

First 1944 (3)	Sixth 1944	12th 1944	15th 1945
E.T.O.	Southern France E.T.O.	E.T.O.	Italy

Armies

First 1918	Second 1918	Third 1918	Fourth 1927	Fifth 1943
E.T.O.	U.S. (training)	E.T.O.	U.S. (training)	Italy

Sixth 1945	Seventh 1943	Eight 1944	Ninth 1944
Pacific	E.T.O.)	Pacific	E.T.O.

Tenth 1944	14th 1944	15th 1944	1stAllied Airborne 1945 (4)	1stAllied Airborne 1945 (5)
Pacific	Not Active	E.T.O.	E.T.O.	E.T.O.

Notes:

1. Date approved as General Headquarters
2. Units assigned directly to General Headquarters
3. The First Army Group was redesignated 12^th Army Group
4. Courtesy Jay Graybeal (original theater made)
5. Variation English-made ("Airborne" rather than "Allied Airborne")