Grotte du Wolfloch

Wolfloch - Trou du Loup

Useful Information

Location: Sentheim.
Meeting point given at registration.
(47.7611876, 7.0323577)
Open: Mid-JUL to mid-AUG Fri 10:30.
Fee: Adults EUR 5, Children (5-12) EUR 3, Family (2+2) EUR 10.
Classification: SpeleologyKarst cave Bajocian-Bathonian Limestone.
Light: bring torch
Guided tours: D=90 min, L=1.5 km, MinAge=5. Français - French
Photography: allowed
Accessibility: no
Address: Maison de la Terre de Haute Alsace, 35 Grand’Rue, 68780 Sentheim, Tel: +33-647-29-16-20. E-mail:
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.



The name Grotte du Wolfloch is a strange mix of French and German, which is rather common in the Alsace, which changed ownership numerous times during the last centuries. The local dialekt is Elsässerisch and is actually a German dialect belonging to Alemannisch. This language is spoken in the whole area, the german speaking part of Switzerland, the Elsaß and the Schwarzwald. There were even ideas to unite the three regions to a new country Alemannia. The locals simply call this cave Wolfloch (wolf hole) which is sometimes translated to the French Trou du Loup. But the French-German pleonasm Grotte du Wolfloch has become the official name.

The Wolfsloch is located in a depression called Bear Pit (Fosse aux Ours, Bärengrube), however there are neither bears nor wolves to expect on a visit. It was freely open, but due to the drop at the entrance tricky to visit. A few years ago the Maison de la Terre de Haute Alsace, a geology museum in the nearby town Sentheim, built a staircase into the cave. As a result it was now easy to enter the cave, and it had to be closed by a gate to protect it from vandalism. There are regular tours to the cave during summer, organized by the museum. So it has become a sort of semi-wild cave or almost-show-cave. Good walking shoes, appropriate clothes, a lamp are much recommended. On the guided tours helmet and headlamp are provided.

They actually did no development inside the cave passage, the passage is horizontal and there is a trail in the cave clay created by the feet of the visitors. Some walls inside the cave are of unknown origin and much older, there are guesses that the cave was used as an air raid shelter. Some stuff like wooden benches was probably brought in by the local youths. The cave has almost no speleothems, but some nice solutional forms. The so-called "calcite flowers" which are mentioned on some pages are a hoax. The cave contains wood and other organic matter which is decomposed by fungi, the white fibrous structures are small pieces of organic matter with fungus growing on it.

This cave is unique for the Alsace, because it is actually a karst cave. Most of the region is crystalline basement, ore bearing granites and metamorphites. But the graben of the Rhine river is filled with much younger sedimentary rocks, including limestones. Such a layer of Bajocian-Bathonian limestone forms the hills around Sentheim and it is karstified. The limestone is quarried. This is the only karst cave in the Alsace open to the public. There are few other caves, and they are either erosional caves or tectonic caves.

The cave is stop 12 on the Sentier Géologique (Geological Trail). The trail is very interesting and freely accessible without restrictions. We recommend early spring, because without plants it's easier to see the geotopes. However, it is not possible to enter the cave because it is gated, except on the regular guided tours by the museum. A topographic map and a leaflet about the trail are available from the museum, which is also the starting point of the trail.