The Grands Causses are a limestone hill country with plateaus at an altitude between 700 and 1200 m asl. It is bordered by the Aubrac to the north, the Cévennes to the east, the Languedoc to the south, and the Lévézou to the west. As a geographic region, its extent does not follow political borders and belongs to two different régions: Midi-Pyrénées and Languedoc-Roussillon.
There are seven different plateaus, which are:
The whole area is composed of karstified limestone. The amount, size, and spectularity of the karst features is extraordinary. This is the cradle of modern speleology, as this was the holiday destination of E. A. Martel who visited his first caves here during his summer holidays.