The most desert-loving large ungulate, occurring in areas of extreme temperature and aridity (less than 100 mm annually) (Newby 2013). With the exception of truly mountainous areas, Addax have been recorded from all major habitat types in the Sahara, from gravelly and sandy plains, to dune fields, sandy basins and depressions, pans and wadi systems; their preference is for harder, packed sands and flatter areas within and between dune fields that support perennial vegetation (Newby 2013, and references therein).

Addax are nomadic, wandering over large areas in search of grazing. In the Sahel, movements tend to be north-south in direction, for example from the more arid desert to the less arid sub-desert and Sahel (Gillet 1965, Newby 1978). In central Niger, movement may also be east-west, for example from the open desert towards the better-wooded and more varied habitats of the Aïr and Termit mountains (Hue 1960). The Addax is well known for its utilisation of extremely desolate, inhospitable, and arid habitats (Dragesco-Joffé 1993).

Addax were formerly widespread in the Sahelo-Saharan region of Africa, west of the Nile Valley, and present in suitable habitats in all countries sharing the Sahara Desert (Newby 2013). As with other ungulates of the Sahelo-Saharan fauna, the Addax has undergone an unprecedented reduction in geographical range (up to 99%) over the past century (Durant et al. 2013). The only known remaining population thought to be viable survives in the Termit/Tin Toumma region of Niger. However, there are sporadic records of small isolated groups and individuals from eastern Aïr Mountains/Western Ténéré desert in Niger, and from the Djourab region of western Chad (Newby 2013). Possible rare vagrants from these areas may be seen in northern Niger, southern Algeria and Libya (Newby 2013). There have been rumours of Addax along the Mali/Mauritania border (Majabat Al Koubra), but no confirmed sightings for several years. In early March 2007, the fresh tracks of about 15 Addax were seen in central Mauritania, in an area where they had not been reported for over 20 years (R. Vernet in Newby 2013), but these reports have not been followed up and it is unclear whether any Addax survive in Mauritania.

Listed on CMS (the Convention on the Conservation of Migratory Species of Wild Animals) Appendix I and CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) Appendix I, and included in the CMS Sahelo-Saharan Antelopes Action Plan (Beudels-Jamar et al. 2005). It is protected under national legislation in Morocco, Tunisia, and Algeria; in Libya and Egypt hunting of all gazelles is forbidden by law.

Although massive reserves, such as the Ahaggar (4,400,000 ha) and Tasilli (1,140,000 ha) in Algeria; Aïr/Ténéré (7,736,000 ha) and Termit-Tin Toumma in Niger, and Ouadi Rimé-Ouadi Achim (7,795,000 ha) in Chad, cover areas where Addax previously occurred, some are under-resourced and only Termit still harbours Addax (Newby 2013). Continued support for reserves in Chad and Niger, together with the establishment of new protected areas, especially along the Mali/Mauritania frontier (Majabat), Niger (Termit/Tin Toumma) and Chad (Bodélé, Egueï), is essential, but must be supported and combined with programmes to create incentives for the local people to protect wildlife wherever it is found (Newby 2013).

Addax have been released into fenced enclosures inside Haddej N.P., Djebil N.P. and Senghar N.P. in Tunisia (Molcanova and Wacher 2010) and numbered around 130 in 2015. About 350 Addax are mainatained in the Rokkein enclosure in Souss-Massa N.P., and Morocco, and a few more are kept in a small, 600 ha breeding enclosure at Safia, just north of the border with Mauritania.

The global captive population numbers ca 760 in Europe, North America, Japan and Australia in managed breeding programmes. There are an estimated 5,000 in private collections and ranches in the United States and the Middle East.