The Elrhaz Formation is a geological formation in Niger, West Africa.

The Ténéré is a desert region in south central Sahara. It comprises a vast plain of sand stretching from northeastern Niger to western Chad, occupying an area of over 400,000 square kilometres (150,000 sq mi). The Ténéré's boundaries are said to be the Aïr Mountains in the west, the Hoggar Mountains in the north, the Djado Plateau in the northeast, the Tibesti Mountains in the east, and the basin of Lake Chad in the south. The central part of the desert, the Erg du Bilma, is centred at approximately 17°35′N 10°55′E. It is the locus of the Neolithic Tenerian culture.