Teysachaux, Mountain summit in Canton of Fribourg, Switzerland.

Teysachaux is a summit reaching 1909 meters with sedimentary rock formations and multiple hiking paths along its steep slopes. The paths are marked and allow exploration of different elevations and mountain conditions.

In 1870, a two-metre-long ichthyosaur fossil, 175 to 183 million years old, was found at the foot of the western slope. The name comes from patois: taiza ("spread") and chaux ("mountain pasture"). Alpine chalets, some now small restaurants, were built on the slopes in the 18th and 19th centuries as dairy farming moved higher.

Local herders use traditional mountain pastures surrounding the mountain to produce regional cheese varieties following methods passed down through generations. These practices shape how the landscape looks and changes with the seasons.

The circular trail starts at Les Rosalys with marked paths, but requires proper mountain gear and weather monitoring during the climb. Plan sufficient time and bring water and protective equipment, as conditions can change quickly.

In 1870, a two-metre-long ichthyosaur fossil, 175 to 183 million years old, was found at the foot of the western slope. Studied many times since, it is now in the permanent exhibition of the Natural History Museum of Fribourg.