Initially, three divisions would land by sea, supported by two airborne brigades. Montgomery quickly expanded this to five divisions by sea and three by air.
A total of 47 divisions would be deployed for Operation Overlord; 26 divisions of British, Canadian, Commonwealth troops and free Europeans, and 21 American divisions.
Under Admiral Bertram Ramsay, the invasion would involve the use of more than 6,000 vessels, including 4,000 landing craft and 130 warships for the bombardment of the coast. In addition, 12,000 aircraft under the command of Air Marshal Trafford Leigh-Mallory were to be used to support the landings, including 1,000 transport planes to ferry the 20,000 paratroopers and airborne troops. 5000 tons of bombs were used against the German coastal defences. According to documents from the General Eisenhower Archive, 7,000 ships (in total) took part in the invasion, both those directly involved and those not directly involved.
In the first forty days the following objectives were to be achieved:
The commanders agreed that the landing areas had to be united as soon as possible into one continuous bridgehead.
By the evening of June 7, the British had a continuous bridgehead about 35 kilometres wide and the town of Bayeux had been captured. At the same time the American sectors were still far apart and there was no connection with a British sector. In the morning of June 8, there was a connection between the American sector at Omaha Beach and the British in the sector Gold Beach. After this connection was made, Bradley went to work to make contact between the sectors Omaha and Utah Beach. The first contact between these two sectors was made on 10 June. However, this was via a country road and in order to have a good connection, first the traffic junction Carentan had to be taken.
This full connection took place on June 12 when the battle of Carentan was decided in the American favour. So on the seventh day after the landing (D-day +7) a complete connection between all sectors was achieved and a bridgehead of 125 km wide was formed.
The Battle of Cherbourg, and certainly its capture, was one of the Allies’ most important objectives in the early stages of Operation Overlord. The capture of an intact major port was crucial to a successful advance against the Germans in Western Europe. But of course the Germans knew this too. They had fortified Cherbourg on all sides in a 15 km perimeter consisting of forts and bunkers.
The last port fort in the Cherbourg area capitulated on June 29.
The port of Cherbourg, the focus of the campaign, lay in ruins. By June 7, German naval personnel had already begun a systematic programme of destruction. It took the Americans almost three weeks to restore the port to service and even then, for months afterwards, it could only operate at partial capacity.
The Battle of Caen played an important role for the Allies because this city was an essential junction of important access roads.
Montgomery knew he could not postpone the conquest and thus the Battle of Caen any longer. He would have to attack the city head-on. To limit the number of British casualties, he decided to ask the RAF on July 6 to force a breakthrough by means of a heavy bombardment.
On July 18 the 3rd Canadian Division succeeded in driving the Germans out of Caen for good. But the battle for Caen had taken its toll. The city and the surrounding villages were largely destroyed.
At the end of June, the Americans again attacked the city of Saint-Lô. The Germans had built up a strong defensive line, which proved stronger than the Americans had expected. The Germans had entrenched themselves between the ruins of the city. The Americans tried to drive them out of the city with small attacks, but they put up fierce resistance. This led the American army command to launch a large-scale offensive on July 3. This attack ended in fighting among the ruins of Saint-Lô. The Americans managed to drive the Germans out of the city on July 18, but at the cost of heavy losses. No fewer than 11,000 men were killed or wounded. Despite these losses, the Americans launched Operation Cobra a few days later, supported by Operation Bluecoat, to force a definitive breakthrough to the south.
After the breakthrough of Operation Cobra, the Germans could only retreat through the east, south of Caen. In other words, they were surrounded and the gap threatened to close at the town of Falaise. This retreat was later given the name ‘Falaise pocket‘.
From August 19 onwards, confrontations between the Parisian resistance and the German troops in the city increased. The fighting reached a climax on August 22.
The French 2nd Armoured Division, under Leclerc, was ordered to enter the city. Heavy fighting followed in the city.
Despite Hitler’s order to General Dietrich von Choltitz to hold Paris at all costs and destroy the city, he surrendered the city on August 25. That same day Charles de Gaulle, leader of the Free French Forces, entered the city and took up residence in the War Ministry on Rue Saint-Dominique.
The liberation of Paris is generally regarded as the end of Operation Overlord.