<P> The United States declared war on Germany on April 6 , 1917 , during World War I . The U.S. was an independent power and did not officially join the Allies . It closely cooperated with the Allies militarily but acted alone in diplomacy . 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 ( C - in - C ) of the American Expeditionary Force ( AEF ) , arrived in large numbers on the Western Front in the summer of 1918 . Before entering the war , the U.S. had remained neutral , though it had been an important supplier to Great Britain and the other Allied powers . During the war , the U.S. mobilized over 4 million military personnel and suffered 110,000 deaths , including 43,000 due to the influenza pandemic . 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 . After a relatively slow start in mobilizing the economy and labor force , by spring 1918 , the nation was poised to play a role in the conflict . Under the leadership of President Woodrow Wilson , the war represented the climax of the Progressive Era as it sought to bring reform and democracy to the world , although there was substantial public opposition to U.S. entry into the war . </P>
<P> The United States declared war on Germany on April 6 , 1917 , during World War I . The U.S. was an independent power and did not officially join the Allies . It closely cooperated with the Allies militarily but acted alone in diplomacy . 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 ( C - in - C ) of the American Expeditionary Force ( AEF ) , arrived in large numbers on the Western Front in the summer of 1918 . Before entering the war , the U.S. had remained neutral , though it had been an important supplier to Great Britain and the other Allied powers . During the war , the U.S. mobilized over 4 million military personnel and suffered 110,000 deaths , including 43,000 due to the influenza pandemic . 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 . After a relatively slow start in mobilizing the economy and labor force , by spring 1918 , the nation was poised to play a role in the conflict . Under the leadership of President Woodrow Wilson , the war represented the climax of the Progressive Era as it sought to bring reform and democracy to the world , although there was substantial public opposition to U.S. entry into the war . </P>
when did the united states enter the war in europe
when did the united states enter the war in europe
April 6 , 1917
April 6 , 1917