The German defence line in the west, the Westwall, was nearby and the occupiers had moved into positions behind the border river Worm. Rimburg Castle, located on the German bank of the Worm, was a stronghold in the defence line.

The German soldiers were able to penetrate the medieval castle and attack the Americans over and over again thanks to an underground system of corridors. The battle for the castle lasted three days. Irreplaceable art treasures were lost in the process.

On 2 October, Rimburg was liberated and the Americans broke through the Westwall at this point. The next phase in the encirclement of Aachen could begin. The battle had cost the lives of more than one hundred soldiers.