U.S. Involvement in World War I By dzieg001 Jul 1, 1914 War Begins May 7, 1915 Sinking of RMS Lusitania Jan 1, 1917 Zimmerman Telegram Mar 15, 1917 German U-Bots Sink U.S. Merchant Vessels Apr 6, 1917 U.S. Declares War on Central Powers Jun 1, 1917 First U.S. Troops Arrive in France May 1, 1918 One Million U.S. Soldiers in France May 28, 1918 First U.S. Offensive, Battle of Cantigny Nov 11, 1918 Armistice Day
