"The Normandy invasion took place in the Bay of the Seine, on the south side of the English Channel between the Cotentin Peninsula and the port of Le Havre. Some fifty-five miles broad and twenty deep, its waters were shallow, had a considerable tidal range, and, when the wind blew from the northward, could be very choppy. The planned landing beaches covered about forty-five miles of the Bay's shoreline. Westernmost was 'Utah' Area, stretching eight miles southward along the low-lying southeastern coast of the Cotentin Peninsula. Directly to the east was 'Omaha' Area, covering twelve miles of generally hilly terrain. United States forces were assigned to take both of those areas, with important assistance from the navies of Great Britain and other Allies. British and Canadian troops would assault the areas code-named 'Gold', 'Juno', and 'Sword', which ran twenty miles eastward from 'Omaha'. This sector ended at the mouth of the Orne River, some fifteen miles west of Le Havre, where the German Navy based a group of potentially very dangerous torpedo boats.

The actual landing beaches occupied a fraction of the width of each area, but were intended to provide sufficient initial footholds to allow rapid reinforcement and expansion inland, with the attacking soldiers joining their flanks to create a continuous beachhead perimeter before the enemy could mount a major counterattack..."

Click on the following link from the U.S. Naval History and Heritage Command to read more: https://www.history.navy.mil/our-collections/photography/wars-and-events/world-war-ii/d-day.html