The Falaise Pocket or Battle of the Falaise Pocket (12 – 21 August 1944) was the decisive engagement of the Battle of Normandy in the Second World War. A pocket was formed around Falaise, Calvados, in which the German Army Group B, with the 7th Army and the Fifth Panzer Army (formerly Panzergruppe West) were encircled by the Western Allies. The battle is also referred to as the Battle of the Falaise Gap (after the corridor which the Germans sought to maintain to allow their escape), the Chambois Pocket, the Falaise-Chambois Pocket, the Argentan–Falaise Pocket or the Trun–Chambois Gap. The battle resulted in the destruction of most of Army Group B west of the Seine, which opened the way to Paris and the Franco-German border for the Allied armies on the Western Front.
Six weeks after D-Day, the Allied invasion of Normandy on 6 June 1944, the German Army was in turmoil. While the Allied Army experienced great difficulty in breaking through the German lines (the city of Caen was supposed to have been captured on the first day of the invasion and was not taken until late in July) the German Army's defence of this area of Normandy was expending irreplaceable resources. The Allied air forces controlled the skies (up to 100km behind enemy lines), bombing and strafing Axis troops, reinforcements, and necessary army supplies, such as fuel and ammunition. On the Eastern Front, the Soviet Union's Operation Bagration and the Lvov–Sandomierz Offensive were in the midst of destroying the German Army Group Centre. In France, the German Army had used its available reserves (especially its armour reserves) to buttress the front lines around Caen, and there were few additional troops available to create successive lines of defence. To make matters worse, the 20 July plot—in which officers of the German Army, including some stationed in France, tried to assassinate Adolf Hitler and seize power—had failed, and in its aftermath there was very little trust between Hitler and his generals.
In order to break out of Normandy, the Allied armies developed a multi-stage operation. It started with a British and Canadian attack along the eastern battle line around Caen in Operation Goodwood on 18 July. The German Army responded by sending a large portion of its armoured reserves to defend. Then, on 25 July thousands of American bombers carpet bombed a 6000-metre hole on the western end of the German lines around Saint-Lô in Operation Cobra, allowing the Americans to push forces through this hole in the German lines. After some initial resistance, the German forces were overwhelmed and the Americans broke through. On 1 August, Lieutenant General George S. Patton was named the commanding officer of the newly recommissioned US Third Army—which included large segments of the soldiers that had broken through the German lines—and with few German reserves behind the front line, the race was on. The Third Army quickly pushed south and then east, meeting very little German resistance. Concurrently, the British and Canadian troops pushed south (Operation Bluecoat) in an attempt to keep the German armour engaged. Under the weight of this British and Canadian attack, the Germans withdrew; the orderly withdrawal eventually collapsed due to lack of fuel.
Despite lacking the resources to defeat the US breakthrough and simultaneous British and Canadian offensives south of Caumont and Caen, Field Marshal Günther von Kluge, the commander of Army Group B, was not permitted by Hitler to withdraw but was ordered to conduct a counter-offensive at Mortain against the US breakthrough. Four depleted panzer divisions were not enough to defeat the First US Army. The disastrous Operation Lüttich drove the Germans deeper into the Allied envelopment.
On 8 August, the Allied ground forces commander, General Bernard Montgomery, ordered the Allied armies to converge on the Falaise–Chambois area to envelop Army Group B, with the First US Army forming the southern arm, the British the base, and the Canadians the northern arm of the encirclement. The Germans began to withdraw on 17 August, and on 19 August the Allies linked up in Chambois. Gaps were forced in the Allied lines by German counter-attacks, the biggest being a corridor forced past the 1st Polish Armoured Division on Hill 262, a commanding position at the mouth of the pocket. By the evening of 21 August, the pocket had been sealed, with c. 50,000 Germans trapped inside. Many Germans escaped, but losses in men and equipment were huge. A few days later, the Allied Liberation of Paris was completed, and on 30 August the remnants of Army Group B retreated across the Seine, which ended Operation Overlord.