<P> The American Expeditionary Forces (A.E.F., A.E.F. or AEF) was a formation of the United States Army on the Western Front of World War I . The AEF was established on July 5, 1917, in France under the command of Gen. John J. Pershing . It fought alongside French Army, British Army, Canadian Army, and Australian Army units against the German Empire . A minority of the AEF troops also fought alongside Italian Army units in that same year 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 . </P> <P> 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 entire 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 decimated 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 Empire tried to bargain with its spare shipping to make the United States put its soldiers into British ranks . </P> <P> By June 1917, only 14,000 American soldiers had arrived in France, and the AEF had only a minor participation at the front through 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 ports in New York City, New Jersey, and 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 1,000 miles (1,600 km) of additional standard - gauge tracks, and over 100,000 miles (160,000 km) of telephone and telegraph lines . </P> <P> 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 21, 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 . </P>

When did us troops arrive in france ww1