On September 26, 1918, the beginning of the Meuse-Argonne Offensive More than 1 million American soldiers in the largest and most costly offensive of WWI were deployed. From the article:
"The Meuse-Argonne Offensive (also known as Battles of the Meuse-Argonne and the Meuse-Argonne Campaign) was a major part of the final Allied offensive of World War I that stretched along the entire Western Front. It was fought from September 26, 1918 until the Armistice of November 11, 1918, a total of 47 days. The Meuse-Argonne Offensive was the largest in United States military history, involving 1.2 million American soldiers. It was one of a series of Allied attacks known as the Hundred Days Offensive, which brought the war to an end. The battle cost 28,000 German lives, 26,277 American lives and an unknown number of French lives. It was the largest and bloodiest operation of World War I for the American Expeditionary Force (AEF), which was commanded by General John J. Pershing, and the deadliest battle in American history. U.S. losses were exacerbated by the inexperience of many of the troops and the tactics used during the early phases of the operation. Meuse-Argonne was the principal engagement of the AEF during World War I.
The logistic prelude to the Meuse attack was planned by then Colonel George Marshall who managed to move American units to the front after the Battle of Saint-Mihiel. The September/October Allied breakthroughs (north, centre, and south) across the length of the Hindenburg Line – including the Battle of the Argonne Forest – are now lumped together as part of what is generally remembered as the Grand Offensive (also known as the Hundred Days Offensive) by the Allies on the Western Front. The Meuse-Argonne offensive also involved troops from France, while the rest of the Allies, including France, Britain, and its dominion and imperial armies (mainly Canada, Australia, and New Zealand), and Belgium contributed to major battles in other sectors across the whole front.
The French and British armies' ability to fight unbroken over the whole four years of the war, in what amounted to a bloody stalemate, is credited by some historians[who?] with breaking the spirit of the German Army on the Western Front, a view which ignores the German Spring_Offensive of 1918. The Grand Offensive, including British, French, and Belgian advances in the north along with the French-American advances around the Argonne forest, is in turn credited for leading directly to the Armistice of November 11, 1918.
On September 26, the Americans began their strike north towards Sedan. The next day, British and Belgian divisions drove towards Ghent (Belgium). British and French armies attacked across northern France on September 28. The scale of the overall offensive, bolstered by the fresh and eager, but largely untried and inexperienced, U.S. troops, signaled renewed vigor among the Allies and sharply dimmed German hopes for victory.
The Meuse-Argonne offensive was the biggest operation and victory of the American Expeditionary Forces (AEF) in World War I. The bulk of the AEF had not gone into action until 1918. The Meuse-Argonne battle was the largest frontline commitment of troops by the U.S. Army in World War I, and also its deadliest. Command was coordinated, with some U.S. troops (e.g. the Buffalo Soldiers of the 92nd Division and the 93rd Division) attached and serving under French command (e.g. XVII Corps during the second phase).
The main U.S. effort of the Meuse-Argonne offensive took place in the Verdun Sector, immediately north and northwest of the town of Verdun, between September 26 and November 11, 1918. However, far to the north, U.S. troops of the 27th and 30th divisions of the II Corps AEF fought under British command in a spearhead attack on the Hindenburg Line with 12 British and Australian divisions, and directly alongside the exhausted veteran divisions of the Australian Corps of the First Australian Imperial Force (1st AIF).[6] With artillery and British tanks, the combined three-nation force, despite some early setbacks, attacked and captured their objectives (including Montbrehain village) along a six-kilometre section of the Line between Bellicourt and Vendhuille, which was centred around an underground section of the St. Quentin Canal and came to be known as the Battle of St. Quentin Canal. Although the capture of the heights above the Beaurevoir Line by October 10, marking a complete breach in the Hindenburg Line, was arguably of greater immediate significance,[7] the important U.S. contribution to the victory at the St. Quentin Canal is less well remembered in the United States than Meuse-Argonne."