The entrance to the cave, at an altitude of 185 metres, overlooks the valley floor some 110 metres below. The cavity is part of a group of cutaneous networks, i.e. of a development running parallel to the main line of the valley, which makes it very likely that there were several entrances. The total length of all of the accessible cave areas does not exceed 235 metres. The level of the cave floor drops 13 meters from the entrance to the Axial Gallery, and 19 metres to the base of the Shaft.

Lascaux has traditionally been divided into seven sectors: the Hall of the Bulls, the Axial Gallery, the Passageway, the Nave, the Chamber of the Felines, the Apse and the Shaft. The accessible areas of the cave can be divided along three major axes. The first comprises the entrance area, the Hall of the Bulls and the Axial Gallery. The second includes the Passageway, the Nave, the Mondmilch Gallery and the Chamber of the Felines. The third axis contains the Shaft and the Great Fissure; beyond this, a large quantity of scree marks the opening of the Silted-up Chamber.