The Western Front of World War I (1914 to 1918): Battles, Timeline and Outcome

The Imperial War Museums call the Western Front the decisive battlefield of World War I, and the National Army Museum agrees that the Allied breakthrough there in 1918 decided the war. For four years it was a line of trenches across Belgium and France where millions of men fought for a few miles of ground. This guide follows the front from the German invasion of 1914 to the Armistice; for a ranking of the war's battles on every front, see our greatest battles of World War I, and for the war's last weeks, how World War I ended.²

Causes of the war on the Western Front

Germany entered the war in 1914 between France and Russia, two allies it could not hope to outlast in a long war. Its answer was the Schlieffen Plan, drawn up by Field Marshal Alfred von Schlieffen and changed by his successor Helmuth von Moltke: throw almost the whole army against France first, swing it through neutral Belgium and Luxembourg around the French border forts, encircle Paris, then turn east against Russia. The Imperial War Museums and the German Historical Museum both point to the plan's great risk: Britain guaranteed Belgian neutrality, so attacking Belgium threatened to bring it into the war.³

On 4 August 1914 German troops entered Belgium, and Britain declared war on Germany the same day; Jonathan Krause dates the start of the march into Belgium and Luxembourg to 3 August. The forts of Liège held out for eleven days instead of the planned two, until heavy siege howitzers broke the last on 16 August, and the Belgian field army fell back on the fortress of Antwerp. When Antwerp fell on 6 October, King Albert took his army to a new line on the Yser River, where flooding stopped the Germans: the left end of the Allied front.⁴

France had its own plan. Its commander in chief, Joseph Joffre, attacked across the German border into Lorraine in August under Plan XVII, believing in the power of the offensive; those attacks were defeated within days with terrible losses, a story told in our article on the Battle of Lorraine. Behind the opening campaign lay a deeper problem that both sides discovered in 1914: machine guns and artillery made open ground deadly for any attacker.⁵

Who fought on the Western Front

On one side stood the German Empire, the main power of the Central Powers in the west. On the other stood France, the British Empire, Belgium and, from 1917, the United States. The British Empire's armies included men from Canada, Australia, New Zealand, South Africa, India, Newfoundland and the Caribbean, who served beside British units on the Somme and at Passchendaele.⁶

The Dominions' corps became some of the most effective formations on the front. All four Canadian divisions attacked together for the first time at Vimy Ridge in April 1917, and in August 1918 the Australian and Canadian corps spearheaded the British Fourth Army's attack at Amiens, with the French First Army attacking alongside.⁷

1914: the Marne, the race to the sea and Ypres

Through August the German right wing pushed the French and the British Expeditionary Force back toward Paris. Then, at the First Battle of the Marne, Joffre struck the exposed German flank: the French Sixth Army attacked on 5 September, the British and the French Fifth Army pushed into a gap that had opened between the German First and Second Armies, and on 10 September the Germans began a general retreat that ended behind the Aisne. The German plan for a short war had failed.⁸

On the Aisne the Germans dug the first trenches of the war. Each side then tried to outflank the other to the north in the mobile fighting of autumn 1914 known as the Race to the Sea, and it ended in Flanders. After the First Battle of Ypres, from 19 October to 22 November 1914 (the National Army Museum dates its start to 20 October), static trench warfare set in, and the Allies held a salient around Ypres that would be fought over for the rest of the war.⁹

By the end of the year trenches ran from the Channel coast to the Swiss border. The sources measure this front differently: the German Historical Museum gives a front line of about 700 km (435 miles), the National Army Museum a trench system of over 600 km (370 miles), the National WWI Museum and Memorial roughly 475 miles of trench systems, and the Imperial War Museums networks stretching over 250 miles (402 km) through France and Belgium.¹⁰

1915 to 1917: trench stalemate, Verdun, the Somme and Passchendaele

In 1915 the British and French made a series of unsuccessful attacks on the German lines, among them the First Battle of Champagne, the Second Battle of Artois and the British attack at Loos in September, the first British use of gas. The Germans made their only Western Front offensive of the year at Ypres: on 22 April 1915 they released some 160 tonnes of chlorine gas from cylinders (Britannica gives about 180) against French and Algerian troops and broke the Allied line. Two days later a second gas attack hit the 1st Canadian Division, which held the line. It was the first large-scale use of poison gas on the Western Front.¹¹

On 21 February 1916 the Germans attacked at Verdun. The German Chief of General Staff, Erich von Falkenhayn, planned to wear down the French army at a place it could not give up, and Fort Douaumont fell on 25 February. Philippe Pétain took over the defense and kept supplies flowing by truck along the Voie Sacrée from Bar-le-Duc, and by December the French had retaken the lost forts. The Mémorial de Verdun counts 163,000 French and 143,000 German dead and missing, and 712,000 casualties in all.¹²

The Allies had agreed on a joint offensive on the Somme in December 1915; after the German attack at Verdun it also had to relieve the French there, and the British took the main role. After a week-long bombardment, the infantry went over the top on 1 July 1916 and met intact German machine guns: the British Army suffered about 57,000 casualties that day, nearly 20,000 of them killed, the bloodiest day in its history (Britannica gives more than 60,000 casualties). On 15 September, at Flers-Courcelette, the British used tanks for the first time. When the offensive ended in mid-November, the Allies had advanced only about 10 km (six or seven miles).¹³

In early 1917 the Germans withdrew to the shorter, fortified Hindenburg Line. The new French commander, Robert Nivelle, promised a breakthrough on the Aisne, supported by British attacks around Arras. On 9 April 1917 the Canadian Corps stormed Vimy Ridge, where earlier French attacks had failed with over 100,000 casualties, and held it by 12 April at a cost of 10,602 Canadian casualties, 3,598 of them killed. But the French offensive on the Chemin des Dames, launched on 16 April, cost 134,000 casualties in nine days by Jonathan Krause's count and was followed by mutinies, and Pétain replaced Nivelle.¹⁴

Douglas Haig's British offensive in Flanders, the Third Battle of Ypres, began on 31 July 1917 and is remembered by the name of its last objective, Passchendaele. Rain turned the shelled ground into waist-deep mud. Herbert Plumer's limited bite-and-hold attacks succeeded in a drier late September, but Haig pressed on into October, and the Canadians finally took Passchendaele ridge on 10 November. The Allies had advanced about five miles.¹⁵

The United States on the Western Front: Belleau Wood and the Meuse-Argonne

The United States stayed neutral until Germany resumed unrestricted submarine warfare on 1 February 1917. On 2 April President Woodrow Wilson asked Congress for a declaration of war against Germany; the Senate voted for it on 4 April and the House two days later. The American Expeditionary Forces under General John J. Pershing grew fast: by late summer 1918 more than a million American soldiers were in France.¹⁶

Their first great test came in June 1918, when a German offensive had reached the Marne again and was advancing toward Paris. The US 2nd Division, including the 4th Marine Brigade, attacked at Belleau Wood on 6 June and, after weeks of close fighting, cleared the wood by 26 June. The French renamed it the Wood of the Marine Brigade. The counts differ: the American Battle Monuments Commission gives 8,100 casualties in the 2nd Division that June, the Marine Corps History Division 9,063 Marine casualties, 1,062 of them killed, and Britannica 9,777 American casualties, 1,811 of them killed.¹⁷

The Meuse-Argonne offensive, from 26 September to the Armistice, was the largest American campaign of the war. More than 1.2 million American soldiers fought through the wooded hills between the Meuse and the Argonne Forest toward the railway junction at Sedan, and 26,277 of them were killed in six weeks. The US National Archives calls it the costliest battle in American military history in terms of casualties. Critics later blamed Pershing for pushing inexperienced troops against strong defenses, while the historian Edward Lengel points to the army's lack of training and the nation's late entry. Our biography of Alvin York tells the story of one of its soldiers.¹⁸

1918: the German spring offensives and the Hundred Days

Russia was knocked out of the war by the revolution of November 1917 and the Treaty of Brest-Litovsk, and Germany moved forces from the east to the west to win before American troops arrived in strength. Its first offensive, launched on 21 March 1918, used brief hurricane bombardments and stormtroopers infiltrating the Allied lines, and it broke the British Fifth Army. At a crisis conference at Doullens on 26 March the Allies gave Ferdinand Foch the coordination of their armies, powers that grew until he became Allied commander in chief. Mobile warfare returned to the Western Front.¹⁹

The German offensives came close to breaking the Allied front, but each one stalled. The last, in the Second Battle of the Marne from 15 July, was met by a French-led counterattack on 18 July, and the initiative passed to the Allies. Foch now struck blow after blow at different parts of the front, giving the exhausted German army no rest.²⁰

At 4:20 am on 8 August 1918 the Australian and Canadian corps led the British Fourth Army's attack at Amiens, with the French First Army attacking alongside, and overran the German front line within hours. Erich Ludendorff later called it the black day of the German army. The Hundred Days Offensive that followed combined infantry, artillery, tanks and aircraft more effectively than before, and from 29 September the Allies broke through the Hindenburg Line on the St Quentin Canal. The Armistice was signed at 5 am on 11 November 1918 and came into effect at 11 am.²¹

The Americans played their part in Foch's plan. They cleared the St Mihiel salient in the first American-led attack of the war (12 to 15 September for the Imperial War Museums, 12 and 13 September for Harold Skinner), then moved to the Meuse-Argonne. Of about two million American troops in France by the end, 1.4 million saw combat, according to King's College London and Skinner.²²

How many soldiers died on the Western Front?

No single agreed total exists for the Western Front, and the sources count battle by battle, often differently. At Verdun the Mémorial de Verdun counts 379,000 French and 333,000 German casualties (the Imperial War Museums 377,000 and 330,000), 163,000 and 143,000 of them dead or missing; the German Historical Museum gives about 250,000 dead on each side. On the Somme the National Army Museum puts British Empire casualties at 420,000, French at 200,000 and German at no fewer than 450,000 killed and wounded; the German Historical Museum gives about 500,000 each for the Germans and the British.²³

At Passchendaele the estimates of British casualties run from about 245,000 (the historian Spencer Jones) to 300,000 (the National Army Museum), and of German casualties from about 200,000 (the Imperial War Museums) to 260,000 (the National Army Museum). In the Meuse-Argonne alone 26,277 Americans were killed.²⁴

Key commanders of the Western Front

• Joseph Joffre (France): commander in chief in 1914, who launched the counterattack on the Marne.
• Erich von Falkenhayn (Germany): Chief of the General Staff, who planned the attack at Verdun.
• Philippe Pétain (France): defender of Verdun in 1916 and commander in chief after the failed Nivelle offensive of 1917.
• Douglas Haig (Britain): commander of the British forces on the Somme and at Passchendaele; Gary Sheffield notes that historians remain divided over his faults and his part in building the effective army of 1918.
• Arthur Currie (Canada): commanded the 1st Canadian Division at Vimy under Julian Byng and led the Canadian Corps at Passchendaele.
• John J. Pershing (United States): commander of the American Expeditionary Forces and of the Meuse-Argonne offensive.
• Erich Ludendorff (Germany): directed the 1918 offensives and called 8 August the black day of the German army.
• Ferdinand Foch (France): given the coordination of the Allied armies in March 1918; his series of blows won the Hundred Days.

Who won the Western Front, and why did Germany lose?

The Allies won. The Hundred Days pushed the German army back toward the battlefields of 1914, and Germany accepted an armistice that amounted to surrender. In 1918 the German army could no longer replace its losses, while the Allies were reinforced by American troops; Jonathan Krause counts nearly thirty fresh German reserve divisions in August and fewer than four in October. Contrary to later Nazi propaganda, Krause stresses, the war in the west was won in the field.²⁶

Historians weigh the causes differently. The Imperial War Museums stress Allied control of the air, coordinated all-arms attacks and falling German morale; King's College London stresses Foch's unified command and Haig's support for it; the Australian War Memorial points to the shift from trench warfare to mobile, combined operations at Amiens. The Somme and Passchendaele are still debated as symbols of futility, but the National Army Museum notes that the tactics learned there laid some of the foundations of 1918.²⁷

Major battles of the Western Front

Our articles on the battles of the Western Front, from the Battle of Lorraine and the siege of Antwerp in 1914 to the Meuse-Argonne in 1918, are listed below in date order.

1. 1914
   First Battle of Champagne, 1914 to 1915France vs German Empire

   On 20 December 1914 Joffre's Fourth Army attacked the German trenches in Champagne. Three months and tens of thousands of casualties later, it had gained three kilometers.

   
2. 1914
   Battle of Lorraine, 1914French Republic vs German Empire

   On 14 August 1914 two French armies invaded German Lorraine under Plan XVII; within a week they were thrown back at Sarrebourg and Morhange.

   
3. 1914
   Battle of Mons, 1914United Kingdom vs German Empire

   On 23 August 1914 the BEF held the canal at Mons against von Kluck's First Army for a day, then retreated. How the fight went, what it cost and where the Angels legend began.

   
4. 1914
   The First Marne, 1914France and Britain vs German Empire

   The counterattack that saved Paris and turned the war into trenches.

   
5. 1914
   Siege of Antwerp, 1914Belgium and Britain vs Germany

   In autumn 1914 German siege guns smashed the forts of Antwerp; the city burned and surrendered on 10 October, but King Albert's army escaped to fight on at the Yser.

   
6. 1914
   First Ypres, 1914Entente vs German Empire

   The battle that froze the Western Front to the sea.

   
7. 1915
   Second Battle of Artois, 1915France (Tenth Army), with the British First Army vs German Empire (Sixth Army)

   On 9 May 1915 Pétain's corps and the Moroccan Division broke through north of Arras and reached the crest of Vimy Ridge within hours. By nightfall they had lost it.

   
8. 1915
   Battle of Loos, 1915British Empire vs German Empire

   On 25 September 1915 the British released chlorine for the first time, two Scottish divisions took Loos and Hill 70, and the reserves came up too late.

   
9. 1916
   The Battle of Verdun, 1916France vs German Empire

   Ten months of grinding slaughter around a French fortress, the longest battle of World War I.

   
10. 1916
    The Somme, 1916Britain and France vs German Empire

    A million casualties and the symbol of industrial war.

    
11. 1917
    Battle of Arras, 1917British Empire vs German Empire

    On Easter Monday 1917 British and Empire troops came out of the tunnels under Arras and broke the German line. Then Monchy-le-Preux and Bullecourt turned the offensive into a costly stalemate.

    
12. 1917
    Battle of Vimy Ridge, 1917Canada (British Empire) vs German Empire (Sixth Army, Group Vimy)

    The Canadian Corps won at Vimy Ridge, 9 to 12 April 1917: four divisions took the whole ridge for 10,602 casualties. A map, the German side and the myth.

    
13. 1917
    Battle of Messines, 1917British Empire vs German Empire

    On 7 June 1917 nineteen British mines exploded under the German ridge south of Ypres, and Irish, British, Australian and New Zealand troops took it in a morning.

    
14. 1917
    The Battle of Passchendaele, 1917British Empire and allies vs German Empire

    Flanders, 1917. A bold plan to break out toward the Belgian coast collapsed into mud, drowning, and attrition. This is the Third Battle of Ypres, remembered as Passchendaele.

    
15. 1917
    Battle of Cambrai, 1917United Kingdom vs German Empire

    On 20 November 1917 476 British tanks broke into the Hindenburg Line at Cambrai and church bells rang in Britain. Ten days later a German counterstroke took most of the ground back.

    
16. 1918
    Battle of Belleau Wood, 1918United States (with French support) vs German Empire

    The US Marines' brutal three-week fight that helped stop the German drive on Paris.

    
17. 1918
    The Hundred Days Offensive, 1918Allied Powers (Britain and the Empire, France, United States, Belgium) vs German Empire

    From Amiens on 8 August to the armistice of 11 November 1918, British Empire, French, American and Belgian armies broke the German army in the west.

    
18. 1918
    Battle of Amiens, 1918British Empire and France vs German Empire

    On 8 August 1918 Canadian, Australian, British and French troops broke the German line east of Amiens in one day. Ludendorff called it the black day of the German Army.

    
19. 1918
    The Meuse-Argonne Offensive, 1918United States (with France) vs German Empire

    More than a million Americans, 47 days, and the end of the war.

    

Timeline of the Western Front

1. 4 August 1914
   Germany invades Belgium; Britain declares war on Germany the same day.²⁸
2. 5 to 12 September 1914
   The Allied counterattack on the Marne halts the German advance.²⁹
3. 19 October to 22 November 1914
   The First Battle of Ypres; trench warfare sets in.³⁰
4. 22 April 1915
   The first large chlorine gas attack, at Ypres.³¹
5. 21 February 1916
   The Germans attack at Verdun.³²
6. 1 July 1916
   The Battle of the Somme begins; tanks follow on 15 September.³³
7. 6 April 1917
   The United States declares war on Germany.³⁴
8. 9 to 12 April 1917
   The Canadian Corps takes Vimy Ridge.³⁵
9. 31 July to 10 November 1917
   The Third Battle of Ypres (Passchendaele).³⁶
10. 21 March 1918
    The first German spring offensive; Foch takes coordination of the Allied armies on 26 March.³⁷
11. 6 to 26 June 1918
    The US 2nd Division fights at Belleau Wood.³⁸
12. 8 August 1918
    The Battle of Amiens opens the Hundred Days.³⁹
13. 26 September 1918
    The Meuse-Argonne offensive begins.⁴⁰
14. 11 November 1918
    The Armistice ends the fighting at 11 am.⁴¹

Where to read next

The Western Front was the decisive front of World War I. For a ranking across all fronts see the greatest battles of World War I, and test yourself with the World War I battles quiz. A generation later the same ground was fought over again: read our hubs on the Western Front of World War II, the Eastern Front, the North African campaign, the Mediterranean theater and the Pacific War.

The war against Russia and Romania has its own guide: the Eastern Front of World War I, from Tannenberg and Gorlice-Tarnów to the Brusilov Offensive and the Treaty of Brest-Litovsk.