The Hundred Days Offensive

Fighting to End the War
Sepia photograph of a WWI-era tank in a line of tanks. Four men sit on top looking at the viewer.

The Hundred Days Offensive was a series of attacks by the Allied troops at the end of World War I. Starting on August 8, 1918, and ending with the Armistice on November 11, the Offensive led to the defeat of the German Army.

By the Summer of 1918, German attacks in the war had halted. Up and down the Western Front the initiative depended on the readiness of the Allies, who now had more soldiers, weapons and materiel than the Germans. French General Ferdinand Foch, commander of all the Allied forces on the Western Front, organized his men to retake the ground lost to the Germans in the Spring and bring a decisive end to the war.

Black and white photograph of a WWI-era tank in a field followed by soldiers on foot.
Postcard with inscription reading "French Tank Leading an Attack Along Marne." Learn more in the Online Collections Database.

The Allies coordinated attacks across the entire front. Starting on August 8, the British Empire forces attacked in Northern France around the city of Amiens. German General Erich Ludendorff described the battle as “the black day of the German Army.” In the middle, the French Army pushed against the German defences known as the ”Hindenburg Line.” At the Sothern end of the Allied attack, the Americans under General Pershing attacked in mid-September, pushing the Germans to St. Mihiel, before beginning a major offensive on September 26 in the Meuse-Argonne.

Black and white photograph of a line of small tanks going through a field. Soldiers ride on the tanks and also walk alongside.
Photograph of British Mark tanks with soldiers walking and riding. Learn more in the Online Collections Database.

This coordinated effort forced German defenses to melt away. For the first time, soldiers on the ground coordinated their efforts alongside tanks, planes and artillery, taking the fight out of the trenches. The trench warfare of the previous four years taught the Allies how to overcome the dug-in German Army, perfecting their expertise in the last days of the Great War. Combat during the Hundred Days became the precursor to the mobile fighting of the Second World War.

Black and white photograph of men in WWI-era military combat gear sitting or standing in a trench.
American soldiers resting in a captured German trench. Learn more in the Online Collections Database.

Yet the victory did not come without cost. The Allies suffered close to 1,070,000 casualties, and the Germans lost 1,172,075, with many becoming prisoners of war. To this day, the Meuse-Argonne remains the bloodiest battle the United States military has ever fought, with over 26,000 killed and 95,000 wounded. The part played by the soldiers of all the Allied nations helped to bring both sides to the peace table, ending not only the Hundred Days Offensive, but the “War to End All Wars” as well.