The Höllentalbahn is a railway line that partially runs through the Höllental valley in the Black Forest of Germany. The line connects Freiburg im Breisgau with Donaueschingen, a distance of 74.7 km (46.4 mi).

The Höllental in the Black Forest is a deep valley - in places like a gorge - in the state of Baden-Württemberg in Germany. The valley, which is about 9 km long, is located in the southern part of the Southern Black Forest Nature Park about 18 km southeast of Freiburg im Breisgau between Hinterzarten and Buchenbach-Himmelreich. The Rotbach stream runs through the valley. "Hölle" is the German word for "hell". In the narrow, dark valley, travellers almost felt like moving underground. The valley was the locale of the Battle of Emmendingen in 1796, part of the French Revolutionary Wars.