The American Expeditionary Forces (AEF) was a formation of the United States Armed Forces on the Western Front during World War I. The AEF was established on July 5, 1917, in France under the command of then-Major General John J. Pershing. It fought alongside French Army, British Army, Canadian Army, British Indian Army, New Zealand Army and Australian Army units against the Imperial German Army. A small number of AEF troops also fought alongside Italian Army units in 1918 against the Austro-Hungarian Army. The AEF helped the French Army on the Western Front during the Aisne Offensive (at the Battle of Château-Thierry and Battle of Belleau Wood) in the summer of 1918, and fought its major actions in the Battle of Saint-Mihiel and the Meuse-Argonne Offensive in the latter part of 1918.
Formation
President Woodrow Wilson initially planned to give command of the AEF to Gen. Frederick Funston, but after Funston's sudden death, Wilson appointed Major General John J. Pershing in May 1917, and Pershing remained in command for the rest of the war. Pershing insisted that American soldiers be well-trained before going to Europe. As a result, few troops arrived before January 1918. In addition, Pershing insisted that the American force would not be used merely to fill gaps in the French and British armies, and he resisted European efforts to have U.S. troops deployed as individual replacements in depleted Allied units. This approach was not always well received by the western Allied leaders who distrusted the potential of an army lacking experience in large-scale warfare. In addition, the British government tried to use its spare shipping as leverage to bring US soldiers under British operational control.
By June 1917, only 14,000 American soldiers had arrived in France, and the AEF had only a minor participation at the front up to late October 1917, but by May 1918 over one million American troops were stationed in France, though only half of them made it to the front lines. Since the transport ships needed to bring American troops to Europe were scarce at the beginning, the U.S. Army pressed into service passenger liners, seized German ships, and borrowed Allied ships to transport American soldiers from the Hoboken Port of Embarkation with facilities in New York City and New Jersey, and the Newport News Port of Embarkation in Virginia. The mobilization effort taxed the American military to the limit and required new organizational strategies and command structures to transport great numbers of troops and supplies quickly and efficiently. The French harbors of Bordeaux, La Pallice, Saint Nazaire, and Brest became the entry points into the French railway system that brought the American troops and their supplies to the Western Front. American engineers in France also built 82 new ship berths, nearly of additional standard-gauge tracks, and over of telephone and telegraph lines.
The first American troops, who were often called "Doughboys," landed in Europe in June 1917. However the AEF did not participate at the front until October 23, 1917, when the 1st Division fired the first American shell of the war toward German lines, although they participated only on a small scale. A group of regular soldiers and the first American division to arrive in France, entered the trenches near Nancy, France, in Lorraine.
I Corps was officially activated in France, under the AEF, from 15 January 1918. It include the 1st, 2nd, 26th, 32nd, 41st and 42nd Divisions. (4th Brigade, US Marine Corps, was included as part of 2nd Division.) II Corps was activated on 24 February, by which time troop numbers justified it. Initially II Corps consisted of the 27th, 30th, 33rd, 78th and 80th Divisions.
In June 1918, many component infantry units from II Corps – commanded by Maj.-Gen. George W. Read – were attached to veteran British Army or Australian Army units. This served two purposes: familiarizing the Americans with actual battlefield conditions in France, and temporarily reinforcing the British Empire units that were often severely-depleted in numbers, after more than three years of fighting. In fact, the first major operation in World War I to involve US troops concerned individual infantry platoons of the 33rd Division, which were attached to battalions of the Australian Corps for the Battle of Hamel on the 4th of July. Their involvement was voluntary and occurred despite last-minute orders from AEF headquarters, that its troops should not take part in offensive operations led by non-US generals. Thus Hamel was historically significant as the first major offensive operation during the war to involve US infantry and the first occasion on which US units had fought alongside British Empire forces.