The Kaouar is a series of ten oases in the southern Sahara in northeast Niger, covering about 75 km (50 mi) from north to south, and 1–5 km (0.62–3.11 mi) east to west. They are on the eastern edge of the Ténéré desert, between the Tibesti Mountains in the east and the Aïr Mountains in the west and between the Fezzan in the north and Lake Chad in the south. They lie on the leeward side of a 100-meter-high north–south escarpment and easterly winds striking the escarpment provide easy access to groundwater for the oases.