Hundred Days Offensive

Hundred Days Offensive
Part of the Western Front of World War I
Western front 1918 allied.jpg
Allied gains in late 1918
Date8 August – 11 November 1918
Amiens, France to Mons, Belgium


Decisive Allied victory


 British Empire

 United States
German Empire Germany
Commanders and leaders
French Third Republic Ferdinand Foch
French Third Republic Philippe Pétain
United Kingdom of Great Britain and Ireland Douglas Haig
United States John J. Pershing
Belgium King Albert I
German Empire Paul von Hindenburg
German Empire Erich Ludendorff
German Empire Wilhelm Groener
Strength on 11 November 1918:[3]
French Third Republic c. 2,559,000
British Empire c. 1,900,000
United States c. 1,900,000[4]
Belgium c. 190,000
Strength on 11 November 1918:[3]
German Empire c. 3,562,000
Casualties and losses
18 July – 11 November:
French Third Republic 531,000
United Kingdom of Great Britain and Ireland 412,000
United States 127,000
18 July – 11 November:
German Empire 1,172,075[5]
785,733 killed or wounded
386,342 captured
6,700 artillery piecesAustria-Hungary 17,500[8]
2,500 killed
5,000 captured
10,000 wounded

The Hundred Days Offensive (8 August to 11 November 1918) was a series of massive Allied offensives which ended the First World War. Beginning with the Battle of Amiens (8–12 August) on the Western Front, the Allies pushed the Central Powers back after their gains from the Spring Offensive. The Germans eventually retreated to the Hindenburg Line, culminating in the Armistice of 11 November 1918 which ended the war with an Allied victory. The term "Hundred Days Offensive" does not refer to a battle or strategy, but rather the rapid series of Allied victories against which the German armies had no reply.


The Spring Offensive of the German Army on the Western Front had begun on 21 March 1918 with Operation Michael and had petered out by July. The Germans had advanced to the River Marne, but failed to achieve their aim of a victory that would decide the war. When Operation Marne-Rheims ended in July, the Allied supreme commander Ferdinand Foch ordered a counter-offensive, which became known as the Second Battle of the Marne. The Germans, recognising their untenable position, withdrew from the Marne to the north. For this victory, Foch was granted the title Marshal of France.

After the Germans had lost their forward momentum, Foch considered the time had arrived for the Allies to return to the offensive. The American Expeditionary Force (AEF) under General John J. Pershing was present in France in large numbers and invigorated the Allied armies with its extensive resources.[9]:472 Pershing was keen to use his army as an independent force. The British Expeditionary Force (BEF) had also been reinforced by large numbers of troops returned from the Sinai and Palestine campaign and the Italian front and replacements previously held back in Britain by Prime Minister David Lloyd George.[9]:155

A number of proposals were considered and Foch agreed on a proposal by Field Marshal Sir Douglas Haig, commander-in-chief of the BEF, to strike on the River Somme, east of Amiens and south-west of the site of the 1916 Battle of the Somme, to force the Germans away from the vital Amiens–Paris railway.[9]:472 The Somme was chosen because it remained the boundary between the BEF and the French armies, along the Amiens–Roye road, allowing the two armies to cooperate. The Picardy terrain provided a good surface for tanks, which was not the case in Flanders, and the defences of the German 2nd Army under General Georg von der Marwitz were relatively weak, having been subjected to continual raiding by the Australians in a process termed peaceful penetration.