The Wehrmacht forces for the Ardennes Offensive were the product of a German recruitment effort targeting German males between the ages of 16 and 60, to replace troops lost during the past five months of fighting the Western Allies on the Western Front. Although the Wehrmacht (German Armed Forces) was keeping the Allied forces contained along the Siegfried Line, the campaign had cost the Wehrmacht nearly 750,000 casualties, mostly irreplaceable. However, the rapid advance of the Allied armies in August and September after Operation Overlord had created a supply problem for the Allies. By October, the progress of the Western Allies' three army groups had slowed considerably, allowing the Germans to partly rebuild their strength and prepare for the defense of Germany itself. Adolf Hitler decided that the only way to reverse his fortunes would be to launch a counter-offensive on the Western Front, forcing both the United States and Great Britain to an early peace, and allowing the Wehrmacht to shift its forces to the Eastern Front, where it could defeat the much larger Soviet Red Army.
Hitler earmarked three field armies for the offensive: the 7th and the Fifth and Sixth Panzer. These accumulated over 240,000 soldiers, spread over seven panzer divisions, two panzer brigades and thirteen infantry divisions. The bulk of the offensive's armored strength was in the Sixth Panzer Army, which was tasked with the capture of the Belgian port of Antwerp. To its south was the Fifth Panzer Army, outfitted to protect the Sixth's flank while it crossed the Meuse river. The southernmost flank was covered by the Seventh Army, composed of three infantry corps and ordered to protect the Fifth Army's southern flank and tie down American reserves in Luxembourg.
Apart from these three armies the Wehrmacht also designed two special units to aid the offensive. One of these was a battalion-sized airborne formation tasked with dropping behind American lines during the first day of the offensive, allowing a panzer division from the Sixth Panzer Army easy access across the Meuse. The second unit was a panzer brigade, intending to go behind enemy lines dressed in American uniforms to give false orders and spread confusion among American defenders in the Ardennes. Also earmarked for the offensive were around 800 aircraft, deployed by the Luftwaffe (German Air Force), to provide air support to German forces and destroy much of the Allied air power on the ground.
To prepare these forces the Oberkommando der Wehrmacht (German High Command) increased the call-up age range and recruited from Eastern European countries controlled by German forces, increasing manpower on the Western Front from roughly 400,000 to just over one million soldiers. Hastily organized into new divisions, these infantrymen lacked training and sometimes even weapons. Despite an immense German effort in the face of intense Allied bombing to build the necessary stocks for the offensive, there were shortages of fuel, ammunition, weapons and manpower by the scheduled date of the counterattack. Even the elite Waffen-SS divisions were often deficient in manpower.
Background
By 1 December 1944, the only sector of the front where the Western Allies were not on the offensive was along the Ardennes. In late July 1944, Allied forces in fighting in Normandy were able to break out of the Normandy beachhead in Operation Cobra, forcing a general eastwards retreat of German forces. General Dwight D. Eisenhower, the Supreme Allied Commander on the Western Front, used the opportunity to encircle the German army in Normandy. In an effort to reverse their misfortunes, the Wehrmacht launched Operation Lüttich on 7 August in the vicinity of the town of Mortain. Despite efforts to break through the U.S. 30th Infantry Division to cut off Allied forces in Northern France, by 13 August it was clear that the offensive had failed. Even while battle was raging around Mortain, Allied armies continued the encirclement of the Wehrmacht in Normandy, closing what would be known as the Falaise Pocket on 20 August; the encirclement cost the Germans an estimated 10,000 dead and another 50,000 wounded. Although a much larger number of German soldiers were able to escape eastwards, they were forced to leave behind their heavy weapons and equipment. Paris was liberated on 25 August 1944, marking the end of Operation Overlord.