The Vercors Massif is a range of plateaux and mountains straddling the départements of Isère and Drôme in the French Prealps. It lies west of the Dauphiné Alps, from which it is separated by the rivers Drac and Isère. The terrain is rugged beyond what the common epithet "plateau" would indicate, and the mainly limestone foundations have created peaks, valleys, gorges, cliffs, and dales - cliffs at its eastern edge face the city of Grenoble. This complexity has led to the area being divided historically into several different regions - the "Quatre Montagnes" (four mountains), the "Coulmes" (gorges), the "Vercors Drômois" (Drome Vercors), the "Hauts-Plateaux" (high plateau) and, in the foothills, Royans, Gervanne, Diois, and Trièves.