USA in the Great War timeline and numbers:
August 1914: ~50 americans join the Légion étrangère.
April 1916: Squadron 124 "Escadrille américaine" is created at Luxeuil-les-Bains.
April 6, 1917: The United States declares war on Germany.
4 million men were drafted into military service. 2 million men were in France by November 1918. 3 million men were draft dodger in the US.
June 13, 1917: John Pershing, AEF commander, and 176 US soldiers arrive at Boulogne-sur-Mer.
June 26, 1917: The 1st US division arrives at Saint-Nazaire. They are sent near Toul, a relatively calm and stable stretch of the frontline.
November 2, 1917: first engagement. A battalion fights at Bathelémont-lès-Bauzemont. 3 KIA.
May 28, 1918: Battle of Cantigny. The first american battle and offensive of WWI. 4,000 men engaged along with french troops.
June 6-22, 1918: Battle of Belleau Wood. 2 US Divisions along with french and british troops.
July 15, 1918: The 3rd US Division earns the nickname "Rock of the Marne" after the Battle of Château-Thierry (part of the Second Battle of the Marne, the last major german offensive on the western front)
September 26, 1918 - November 11, 1918: Meuse-Argonne Offensive (1st US Army and 4th French Army)
November 11, 1918: Armistice
53,402 KIA
63,114 any other cause (accident, disease,...)
Total fatalities: 116,516
204,002 WIA
3,350 MIA