Operation Overlord, launched on D-Day - 6th June 1944 - was the largest military invasion in history, with 156,000 troops landing on the Normandy beaches on the first day alone. Planning for the invasion of Europe began as early as autumn 1940 when the War Office surveyed the Southampton area with a view to using it as a base for a future invasion. The actual build-up began in the spring of 1942 when the Southampton area was designated area ‘C’. Landing craft and other vessels began arriving in the docks in 1942 and the South Western Hotel became HQ of the Combined Operation Military Movement Control. In July 1943 the US Army 14th Major Port Transport Corps arrived in Southampton to co-ordinate the movement of American troops and equipment through the port. Later in 1943, 25 military camps were set up in the area to hold troops before they embarked for Normandy and the Common and the Central Parks were also converted into military camps.
Sections of the Mulberry Harbours, the artificial floating ports that were towed across the Channel to help land troops and equipment after the initial beachheads had been established, were built in Southampton Docks. Some of the pipe lines for PLUTO (Pipe Line Under The Ocean), used for supplying the allied army with fuel, were also constructed locally.
On D-Day itself, Southampton was the embarkation port for British and Canadian assault troops, with two-thirds of the entire British assault force passing through the port. In the weeks following D-Day Southampton was the embarkation port for troops going to France to reinforce the armies there. Between D-Day and the end of the war, about 3,500,000 military personnel passed through Southampton. Military vehicles, equipment and stores were also moved through the port
