At a ceremony at the Mardasson memorial in Bastogne, Belgium, US defence secretary Mark Esper paid tribute to the 19,000 American troops who died.
More than 10,000 German soldiers were killed.
Tens of thousands of troops lost their lives
The offensive began on 16 December 1944 when more than 200,000 German soldiers began to break through dense Belgian woods and Luxembourg’s hilly Ardennes.
Taking advantage of freezing weather and tired US troops, the Germans pierced the front line so deeply that it became known as the Battle of the Bulge.
The Americans pushed back and, after reinforcements had been drafted in, the tide began to turn by Christmas.
The conflict continued until 25 January 1945.
Many German units were severely depleted of personnel and equipment, and the war came to an end in September.
Mr Esper said the battle was “one of the greatest in American history”.
US soldiers’ efforts “not only defended America but also ensured that the peoples of Europe would be free again”, he added.
“It was ultimately the intrepid, indomitable spirit of the American soldier that brought victory,” Mr Esper said.
The conflict began on 16 December 1944
It continued until 25 January 1945
German President Frank-Walter Steinmeier said: “On this day, we Germans would like to thank the United States of America.
“The American armed forces, together with their allies, liberated Europe and they also liberated Germany. We thank you.”
Mr Steinmeier added: “Those who died were victims of hatred, delusion, and a destructive fury that originated from my country.”
