when did the united states entered the first world war
American entry into World War I On December 7, 1917, the U.S. declared war on Austria-Hungary.[5][6]
United States in World War I The U.S. made its major contributions in terms of supplies, raw material and money, starting in 1917. American soldiers under General John Pershing, Commander-in-Chief of the American Expeditionary Force (AEF), arrived in large numbers on the Western Front in the summer of 1918. During the war the U.S. mobilized over 4 million military personnel and suffered 110,000 deaths, including around 45,000 who died due to the 1918 Spanish flu outbreak (30,000 before they even reached France).[1][2] The war saw a dramatic expansion of the United States government in an effort to harness the war effort and a significant increase in the size of the U.S. Armed Forces.