Lacoste is a commune in the Vaucluse department in the Provence-Alpes-Côte d'Azur region in southeastern France.

The Luberon is a massif in central Provence in Southern France, part of the French Prealps. It has a maximum elevation of 1,256 metres (4,121 ft) and an area of about 600 square kilometres (230 sq mi). It is composed of three mountain ranges : Lesser Luberon, Greater Luberon and Eastern Luberon. The valleys north and south of them contain a number of towns and villages as well as agricultural land; the northern part is marked by the Calavon, while the southern part is characterised by the Durance.