The role of the U.S. divisions which fought on Belgian soil during the First World War is not well known because unlike most American divisions fighting in Europe at this time, they were not fighting as part of a purely American force in its own American sector but had been attached to Allied armies to help the exhausted British and French stop the final German offensive in the late spring and summer of 1918 and then stage a major counteroffensive in the autumn of 1918 to push the Germans out of France and Belgium. Thus these divisions were not part of the famous St. Mihiel and Meuse-Argonne Offensives carried out in the autumn of 1918 by the 2nd and 1st US Armies respectively under the command of General John J. "Black Jack" Pershing, Commander of the American Expeditionary Force (AEF) in Europe. http://www.aomda.org/htm/history.shtml#02
One of the American divisions serving under British command was the 27th Infantry also known as the "New York Division." A collection of letters from one Corporal of this division who was killed in action during the Somme Offensive of September, 1918 is published on Soldiers' Mail. Read and enjoy