After the German conquest of France in 1940, the opening of a second front in western Europe was a major aim of Allied strategy during World War II. On June 6, 1944, under the code name Operation "Overlord," US, British and Canadian troops landed on the beaches of Normandy, France, on the English Channel coast east of Cherbourg and west of Le Havre.
Under overall command of General Dwight D. Eisenhower and, on the ground, of British General Bernard Montgomery, more than 130,000 Allied troops landed on five beaches, code named Omaha, Gold, Juno, Sword, and Utah. On the night before the amphibious landings, 23,000 US and British paratroopers landed in France behind the German defensive lines by parachute and glider. The invasion force of more than 155,000 troops included 50,000 vehicles (including 1,000 tanks). Nearly 7,000 naval craft and more than 11,500 aircraft supported the invasion.
Under the overall command of Field Marshall Erwin Rommel, the Germans had deployed five infantry divisions, one airborne division and one tank division along the Normandy coast and held the advantage in battle positioning. However, the Allies had an overwhelming advantage in naval and air power. On D-Day alone, the Allies flew 14,000 sorties; the German air force managed only 500 sorties. Moreover, a successful Allied deception plan had led the Germans to believe the point of the attack to be further north and east on the coast near Calais and the Belgian border. Fooled, the Germans moved only slowly to reinforce the Normandy defenses after the initial landing.
Despite Allied superiority, the Germans contained Allied troops in their slowly expanding beachhead for six weeks. The US 1st and 29th Infantry Divisions made the most difficult landing on Omaha Beach. Stiff German resistance here caused over 3,000 casualties before the Allied troops could establish their positions by the end of the first day. On D-Day itself, Allied troops suffered more than 10,000 casualties: British and Canadian forces suffered around 3,700 casualties; US forces took about 6,600 casualties. The German defenders lost between 4,000 and 9,000 men.
On D-Day itself, the Allies landed 11 divisions on the French coast, but failed in reaching their planned objective of linking the beachheads or driving inland to a distance of nine miles. Within five days, on June 11, Allied troops overcame German resistance to unite the invasion beaches into one large beachhead.
On July 25, 1944, Allied troops broke out of the Normandy beachhead near the town of St. Lo and began to pour into northern France. By mid-August, Allied troops had encircled and destroyed much of the German army in Normandy in the Falaise pocket. Spearheaded by General George Patton's Third Army, the Allies then raced across France. On August 25, Free French forces liberated Paris; on September 16, US troops reached the border of Germany.
Since the Normandy invasion, June 6, 1944 has been known in World War II history as "D-Day."