Turmberg, Mountain peak in Durlach, Germany.

Turmberg is a 256-metre hill in Durlach, Karlsruhe, at the northern edge of the Black Forest. Its summit is made of Muschelkalk limestone and holds the Turmberg ruin, whose surviving tower serves as an observation tower. The Turmbergbahn funicular, built in 1888, ran from the base to the summit until the end of 2024 and is to be rebuilt.

The ruined castle on the Turmberg, also called Hohenberg, was the seat of the margraves of Baden-Durlach until the residence was moved to Durlach in 1565. Its surviving tower later served as a lookout; the funicular railway to the summit opened in 1888. The site is now a popular destination above the Rhine plain.

The hill takes its name from the medieval tower that still stands at its top and can be seen from Durlach below. Locals use the path up as a regular outing spot, and on weekends the summit draws families and walkers who come for the open view over the Rhine plain.

A visit is most rewarding on clear days, when the view over the Rhine plain reaches far into the distance. The funicular runs on a regular schedule, but the hill can also be reached on foot by a marked trail for those who prefer to walk up.

When the funicular opened in 1888, it ran on a water-ballast system where tanks filled with water at the top car were heavy enough to pull the lower car up the slope. The mechanism was later replaced with electric power, but the track itself has not changed since the line first opened.