US Army at the beginning of WW2

Strength and Organization of the US Army in North America, Great Britain and Mediterranean theatre in 1941-42

GI's are landing

GI’s are landing on a Mediterranean coast.

US Army

Although it is true that the United States mobilised its vast resources in a remarkably short time, American soldiers had ample warning of the coming crisis. In 1940 the Army was divided in three: the regulars, the National Guard and the Organised Reserve. The Regular Army numbered 243,095 and was scattered in 130 posts, camps and stations, the men serving short-term enlistments: the officers numbered 1,400. The National Guard was 226,837 strong and was equipped by individual states and received two weeks’ training each summer.

There was, in addition, a reserve of 104,228 officers in the organised reserve corps, composed of the Officer Training Camps. The Army received a standard institutionalised pattern of training: the service schools supervised training and the Service Boards tested and developed new equipment.

The continental United States, the Zone of the Interior, was administered by four armies and, in 1940, they only had skeleton staffs of 4,400 troops each. There were nine infantry divisions; only three had a compliment of regular formations, the other six were only 3,000 strong. There was also a cavalry division and a mechanised brigade of 4,000 and 2,300 men respectively. Responsibility for speeding up mobilisation was given to General Headquarters (GHQ), and in 1941 it was given responsibility for the training of troops under the leadership of General Leslie McNair.

On 17 June 1941 the Army was expanded to 280,000 men and nine days later to 375,000. On 16 September the National Guard units were absorbed into the Army and Roosevelt persuaded Congress to pass the Selective Service Act; by July 1941, 606,915 men were inducted into the Army.
New units were usually formed around the regular or National Guard formations. At first there were 27 divisions, nine regular and 18 National Guard; there were also two armoured divisions and a further three completing their training.

American mobilisation proceeded fairly smoothly before the outbreak of war in December 1941. Thereafter the strain inflicted by the early disasters in the Pacific and the demand for continued expansion proved too much. The War Department originally believed that it could mobilise three or four divisions per month after March 1942, but this rate could not be kept up; by the end of December 1942 only 42 of the planned 73 divisions had been mobilised. Indeed, by September the Army was short of 330,000 men and the ambitious plans laid in that month to create an army of 114 divisions were never realised.

The main factor which limited the size of the US Army, apart from the capacity of the American economy to equip such a large force quickly, was shipping.
The shipping estimates showed that no more than 4,170,000 men could be shipped overseas by the end of 1944. In the event the number of divisions shipped abroad did not exceed 88. This fact was an important restraint on Allied strategy.

Thus although expansion between December 1941 and December 1943 was unprecedented, with the Army growing from 1,657,157 to 5,400,888, a further increase in the number of units was not undertaken. By December 1944, 4,933,682 Americans were serving abroad in 80 divisions; these were supported by a mere three divisions in reserve.

In 1945 the US Army reached a total of 91 divisions, but three of these were broken up for reinforcements. The remaining 88 were maintained at full combat strength despite the fact that by the end of the Ardennes Campaign in January 1945, 47 regiments in 19 divisions had suffered between 100 and 200 per cent battle casualties.

US Army units participating in Operation Torch , the invasion of French North Africa were:
Western Task Force of 35,000 men: 1 armoured division, 2 infantry divisions.
Central and Eastern Task Forces: 1 armoured division, 3 infantry divisions.

While the Western Task Force was composed entirely of US personnel, the Central and Eastern forces also included British troops.


US Army units in 1942
Infantry Division (motorised) Armoured Division Tank Battalion Tank Destroyer Battalion
Total units (in summer 1942) c. 28 (42 in December 1942; including armoured) c. 5 (16 in 1944-45) 2 + (65 in 1944-45, often being combined in groups of 3-5, sometimes with mechanized infantry units) 3 + (80 in 1945)
Infantry regiments 3 (each with three battalions, each with 860 men) 1 (with three battalions, each with 860 men, all mounted on half-tracks)
Total men 14,253 10,900 729 1,250
Machine guns 280 (147 x .30, 133 x .50) c. 93 (49 x .30, 44 x .50) 18 x .30, 26 x .50 30 x .30, 44 x .50
Bazookas 557 (1943) 607 (1943) 25 62
Mortars 138 (81 x 60mm, 57 x 81mm) 46 (27 x 60mm, 19 x 81mm) 6 x 81mm 3 x 81mm
Artillery 48 (36 x US 105mm Howitzer, 12 x US 155mm Howitzer)
Self-propelled howitzers 24 (18 x 75mm, 6 x 105mm) 54 (105mm)
Anti-tank guns 109 (37mm M3A1 , later 57mm) 27 -
Anti-aircraft guns all anti-aircraft battalions were controlled by the commanding Field Army
Vehicles (trucks) 1,440 (note: this capacity was not enough to move all equipment and personnel simultaneously). All types total: 2,653 2,653 (all types, including Jeeps) 64 82
APC's 5 501 (M3 Half-tracks) 13
Armoured Cars 68 (M8) 36
Tanks 227 (159 medium M3 'Lee' or M4 Sherman, 68 Stuart) 68 (51 medium M3 'Lee' or M4 Sherman, 17 Stuart) 36 (M10)
Call of War
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