<P> At the beginning, during the Spring of 1918, the four battle - ready U.S. divisions were deployed under French and British command to gain combat experience by defending relatively quiet sectors of their lines . After the first offensive action and American - led AEF victory on 28 May 1918 at the Battle of Cantigny, by the U.S. 1st Division, and a similar local action by the 2nd Division at Belleau Wood beginning 6 June, both while assigned under French Corps command, Pershing worked towards the deployment of an independent US field Army . The rest followed at an accelerating pace during the spring and summer of 1918 . By June Americans were arriving in - theater at the rate of 10,000 a day; most of which entered training by British, Canadian and Australian battle - experienced officers and senior non-commissioned ranks . The training took a minimum of six weeks due to the inexperience of the servicemen . </P> <P> The first offensive action by AEF units serving under non-American command was 1,000 men (four companies from the 33d Division AEF), with the Australian Corps during the Battle of Hamel on 4 July 1918 . (Corporal Thomas A. Pope was awarded the Medal of Honor for this battle .) This battle took place under the overall command of the Australian Corps commander, Lt. Gen. Sir John Monash . The Allied force in this battle combined artillery, armor, infantry, and air support (Combined arms), which served as a blueprint for all subsequent Allied attacks, using "tanks". </P> <P> U.S. Army and Marine Corps troops played a key role in helping stop the German thrust towards Paris, during the Second Battle of the Marne in June 1918 (at the Battle of Château - Thierry (1918) and the Battle of Belleau Wood). The first major and distinctly American offensive was the reduction of the Saint Mihiel salient during September 1918 . During the Battle of Saint - Mihiel, Pershing commanded the U.S. First Army, composed of seven divisions and more than 500,000 men, in the largest offensive operation ever undertaken by United States armed forces . This successful offensive was followed by the Meuse - Argonne offensive, lasting from September 26 to November 11, 1918, during which Pershing commanded more than one million American and French combatants . In these two military operations, Allied forces recovered more than 200 sq mi (488 km) of French territory from the German army . By the time the World War I Armistice had suspended all combat on November 11, 1918, the American Expeditionary Forces had evolved into a modern, combat - tested army . </P> <P> Late in the war, American units ultimately fought in two other theaters at the request of the European powers . Pershing sent troops of the 332d Infantry Regiment to Italy, and President Wilson agreed to send some troops, the 27th and 339th Infantry Regiments, to Russia . These latter two were known as the American Expeditionary Force Siberia, and the American Expeditionary Force North Russia . </P>

The arrival of american troops in france in 1917