The Ahaggar Mountains, also known as the Hoggar, are a highland region in central Sahara, or southern Algeria, along the Tropic of Cancer. They are located about 1,500 km (900 mi) south of the capital, Algiers and just west of Tamanghasset. The region is largely rocky desert with an average altitude of more than 900 metres (2,953 feet) above sea level. The highest peak is at 3,003 meters (Mount Tahat). Assekrem is a famous and often visited point where le Père de Foucauld lived in the summer of 1905. The main city nearby the Ahaggar is Tamanghasset, built in a desert valley or wadi.
The Ahaggar Mountain range is chiefly volcanic rock and contains a hot summer climate, with a cold winter climate (temperatures fall below 0°C in the winter). The mountains are young—about 2 million years old. Rainfall is rare and sporadic. However, since the climate is less extreme than in most other areas of the Sahara, the Ahaggar Mountains are a major location for biodiversity and host relict species. The Ahaggar Mountains compose the West Saharan montane xeric woodlands ecoregion. It is also one of the national parks of the country.Slightly to the west of the Ahaggar range, a population of the endangered Painted Hunting Dog ( Lycaon pictus) remained viable into the 20th century, but is now thought to be extirpated within this entire region.