United States of America

The United States of America, under President Woodrow Wilson, maintained a policy of neutrality at the start of the War. However, this changed over time, and in April 1917 the US entered the War on the side of the Allies. 

Two million people from the US served in the military overseas during the First World War, including 200,000 naval personnel. 



Nearly 13,000 women joined the navy as Yeoman (F) (for female), and the marines.  More than 20,000 women served in the Army and Navy Nurse Corps.

Entering the War

At the beginning of the War, many people in the US believed that it was a ‘European War’ and that they should not get involved.  However, when a German U-Boat submarine sank the US ship RMS Lusitania in May 1915, public opinion turned against Germany.  

The United States remained legally neutral, and President Wilson hoped they could act as a mediator to end the War.  In 1916 Wilson ran for re-election on a platform of peace, and won with public support.

In 1917 Germany, desperate to end the War, began ‘unrestricted submarine warfare’, and in March sunk five US ships.  This shocked the public, and support for entering the War increased.

Congress declared war on Germany on the 6th of April 1917.


To fuel the Allied War effort, the US government mobilised industry to make weapons, equipment, munitions, and supplies. This created new jobs and opportunities in the industrialising north.

Nearly one million women joined the workforce. Hundreds of thousands of African Americans from the south migrated north to work in factories.  This meant that more Americans than ever before were living in cities and working in manufacturing jobs instead of agricultural ones.

The government used propaganda to encourage people to buy government bonds and war savings stamps, and to work for the War effort. 

The US contributed ammunition, supplies, and machinery to the Allied forces after entering the war, which made a big difference to the outcome of the war.


Two million Americans volunteered for the army, and nearly three million were ‘drafted’ (conscripted).  Some volunteered to join the British forces before the US had even entered the War.

More than 350,000 African Americans served in the First World War.  At this time racial discrimination was legally enforced in the US, and African Americans were segregated from white troops in separate units.

The first contingent of the American Expeditionary Force (AEF) arrived in France in June 1917. They were commanded by General John J. Pershing, and under overall command of Marshall Foch of France.  It took time to assemble, train, and equip a fighting force. By spring 1918, the AEF was ready, first halting a German offensive at the Battle of Belleau Wood.

In August 1918 the US forces became independent from Marshall Foch’s command, and the American First Army (AFA) was formed.  The AFA aimed to reduce the enemy sector at St. Mihiel, and then move north to join other Allied forces for the Meuse-Argonne Offensive. 

1918 Baseball World Series

© the 1918 world series

In September 1918, the baseball World Series was due to be played in Chicago.  This was the biggest baseball game in the US, and the Boston Red Sox were going to play the Chicago Cubs.  The officials wanted to cancel the game out of respect for soldiers fighting in the War. But they soon found out that US troops were excited for the game and desperate for news of the result, so the game went ahead.

For the first time in any baseball game, the band played the new national anthem ‘The Star Spangled Banner’ during the seventh-inning stretch of the game to honour the troops.  All the spectators and players stood up to join in.  Soon it became tradition to play the Star-Spangled Banner at all baseball games and, eventually, nearly all sporting events.  Red Sox supporters who were away from home were delighted to hear the news that their team had won.