U.S. Military History: D-Day

Ross Dunfee

So, what does the “D” stand for in D-Day? Stop! Do not keep reading until you attempt to answer the question. Okay, now you can read on. Most people who celebrate the holiday do not know the answer. Some people believe it is in reference to June 6, 1944, when, in World War II, Allied forces invaded northern France by means of beach landings in Normandy, and that is partially correct.

The first military reference to using “D” in a planning document is found during World War I in Field Order No. 9, (First Army, American Expeditionary Forces) dated Sept. 7, 1918. “The First Army will attack at H Hour on D Day with the object of forcing the evacuation of the St. Mihiel Salient.” The purpose of using “H” for hour and “D” for day was to keep the time and date of the attack secret, or if the day and hour had not yet been determined. That tradition carried into World War II.

Attack planning papers are prepared long before an attack is to occur, so in the planning stage a minus (-) sign was used, or after the attack a plus (+) sign was used. D-5 referred to five days prior to an invasion, and H+7 referred to seven hours after an invasion. Multiple invasions in the European and Pacific Theaters used the “D” designation or had their own letter, such as: L Day for “Landing Day,” April 1, 1945, when Operation Iceberg (the invasion of Okinawa) began; X Day, Nov. 1, 1945, when Operation Downfall (the invasion of Japan) was to begin; V E Day, “Victory in Europe,” designates May 8, 1945 the date when the Allies formally celebrated the defeat of Nazi Germany.

The most famous of D-Day is Operation Overlord, June 6, 1944, the Normandy landings. The assault phase of that invasion, Operation Neptune, lasted until June 30, and Operation Overlord concluded on Aug. 25. One of the largest amphibious military assaults in history placed 156,000 American, British, and Canadian forces along 50 miles of France’s Normandy region. The Allies had conducted a large-scale deception campaign designed to mislead the Germans about the intended invasion target, and, by late August 1944, northern France had been liberated.

General Dwight Eisenhower, commander of Operation Overlord, originally selected June 5 as D-Day, but foul weather forced a delay in the plans. On the morning of June 6 (D+1), more than 5,000 ships and landing craft carrying troops and supplies left England for the trip across the Channel to France, while more than 11,000 aircraft were mobilized to provide air cover and support for the invasion. More than 2,000 American soldiers sacrificed their lives that day. By June 11 the beaches were fully secured, and over 326,000 troops (about half the population of Wyoming), more than 50,000 vehicles, and some 100,000 tons of equipment had landed at Normandy.

Support Our Troops–Arizona proudly places 370 U.S. flags along the principal roads in Robson Ranch on D-Day to honor the military personnel who, through the various invasions in the European and Pacific Theaters, sacrificed so much for our freedoms. For questions about this article, contact Ross Dunfee at [email protected]. To learn more about how SOT–AZ supports veterans, contact Steve Reeves, president, at [email protected].