11 a.m. November 11, 1918, Armistice Day, the day hostilities stopped on the western front. Yet over 3000 American graves have this date. Men died in the last hours of the war. Henry N. Gunther, for example, died at 10:59 am on Armistice Day. He was the last American casualty of the war. You may think, perhaps the soldiers did not know the armistice had been signed, but the official signing happened earlier that morning, actually taking effect at 11. News of this was widespread across the front with a few hours. Officers were not explicitly told to stand down, in the meantime, it was left to each officer to decide what to do. Some officers decided to keep fighting, after all the last town captured by the Americans was taken for the sake of baths. After the war, Congress created subcommittee 3 to discuss the losses on that day. To explain why men died, seemingly needlessly, in the final hours of the war. General Pershing, commander of American forces on the western front, told Congress “No one could possibly know when the armistice was to be signed, or what hour be fixed for the cessation of hostilities so that the only thing for us to do, and which I did as commander in chief of the American forces, and which Marshal Foch did as commander in chief of the Allied armies was to continue the military activities.” Men were forced to risk their lives just in case the starving Germans might try to retaliate.

Source:

http://www.historynet.com/world-war-i-wasted-lives-on-armistice-day.htm