The term D-Day River refers to the River Orne in Normandy, France. It was a crucial part of the Allied invasion of Europe during World War II, as it was the site of the first landings on June 6th, 1944. The river was used by the Allies to launch their amphibious assault on German forces, and its banks were heavily defended by the Germans. The crossing of the River Orne was a major turning point in the war, and it is remembered today as one of the most significant battles of the conflict.