The Hundred Days Offensive ended World War I by driving German forces back across the Western Front and compelling the Armistice of 11 November 1918.
Key Facts
- Duration
- 8 August – 11 November 1918
- Opening battle
- Battle of Amiens, 8–12 August 1918
- Key breakthrough
- Battle of St Quentin Canal, 29 September 1918
- Result
- Armistice of 11 November 1918; Allied victory
- Theater
- Western Front
By the Numbers
Location
Cause → Event → Consequence
Germany's spring offensive of 1918 (21 March – 18 July) had temporarily pushed Allied lines back, but exhausted German reserves and overstretched supply lines. By August, Allied forces under unified command had regrouped and accumulated sufficient strength, materiel, and coordination to mount a sustained counter-offensive along the Western Front.
Beginning with the Battle of Amiens on 8 August 1918, Allied forces launched successive large-scale attacks that drove the Imperial German Army steadily eastward, undoing the gains of the spring offensive. German troops fell back to the Hindenburg Line, which was itself breached at the Battle of St Quentin Canal on 29 September, triggering a rapid and continuous Allied advance through October and into November.
The unrelenting Allied pressure collapsed German military resistance and morale, leading directly to the Armistice of 11 November 1918. Germany's defeat ended the First World War with a clear Allied victory, dissolved the German Imperial government, and set the diplomatic stage for the peace negotiations that produced the Treaty of Versailles in 1919.
Belligerents & Mobilization Analysis
Side A
3 belligerents
Side B
1 belligerent