Sahara Desert

Largest hot desert, spanning North Africa.

The Sahara is composed of rocky plateaus, sand seas, gravel plains, dry valleys, dry lakes, and salt flats, with many sand dunes rising over 180 m.^[1] The northern limit corresponds to the northern limit of date palm cultivation and the southern limit of esparto grass.^[2] During the last glacial period, the Sahara was much larger than it is today, extending south beyond its current boundaries.^[3] Algeria, Chad, Egypt, Libya, Mali, Mauritania, Niger, Western Sahara, and Sudan are largely within the Sahara, as are portions of southern Morocco and Tunisia.^[4]

The Sahara's northern edge runs along the Mediterranean Sea in Egypt and parts of Libya, and in Cyrenaica and the Maghreb it meets the Mediterranean forest, woodland, and scrub eco-regions.^[2] A belt of dry tropical savanna known as the Sahel forms the Sahara's southern boundary.^[5] Over hundreds of thousands of years, the Sahara has shifted between desert and savanna grassland every 20,000 years, a cycle driven by the precession of Earth's axis.^[6][7] The monsoon had moved southward to roughly its present position by about 4200 BCE, which initiated the Sahara's gradual transformation into desert.^[8][9]

Last updated 2026-10-03 from the source article.

Quick Facts

Type: Hot desert
Location: North Africa
Highest peak: Emi Koussi, a shield volcano in the Tibesti range of northern Chad

Facts from the source article.

What the cited sources add

The "Largest Desert in the World" record notes that a desert receives less than 250 mm of precipitation per year.^[10] The same source states that the two largest deserts on Earth are in the polar areas, with the Antarctic Polar Desert covering about 5.5 million square miles.^[10] The WorldAtlas article lists the Sahara as the largest subtropical desert, clocking in at 3.5 million square miles.^[11] The MIT News article by Chu reports that researchers found the Sahara has swung between wet and dry climates every 20,000 years, driven by changes to Earth's axis.^[7]

The ScienceDaily article notes that the CLIMBER-2 model concluded desertification of North Africa began abruptly 5,440 years ago.^[9] The same article states that before that time, the Sahara was covered by annual grasses and low shrubs, as evidenced by fossilized pollen.^[9]

References

Wikipedia, "Sahara" (CC BY-SA 4.0), which cites: ; Strahler, Arthur N. and Strahler, Alan H. (1987) Modern Physical Geography Third Edition. New York: John Wiley & Sons. . p. 347 (original not read by us) en.wikipedia.org
Wikipedia, "Sahara" (CC BY-SA 4.0), which cites: Wickens, Gerald E. (1998) Ecophysiology of Economic Plants in Arid and Semi-Arid Lands. Springer, Berlin.; Grove, A.T., "The Ancient Erg of Hausaland, and Similar Formations on the South Side of the Sahara", The Geographical Journal, 2007, p. 528–533; Bisson, J., "Mythes et réalités d'un désert convoité: le Sahara", L'Harmattan, 2003 (original not read by us) en.wikipedia.org
Wikipedia, "Sahara" (CC BY-SA 4.0), which cites: Ehret, Christopher, The Civilizations of Africa, University Press of Virginia, 2002.; "Fezzan Project - Palaeoclimate and environment", May 2026 (original not read by us) en.wikipedia.org
Wikipedia, "Sahara" (CC BY-SA 4.0), which cites: Farr, "Exocartographer: A Bayesian Framework for Mapping Exoplanets in Reflected Light", The Astronomical Journal, 2018, p. 146 (we also read that source) en.wikipedia.org
Wikipedia, "Sahara" (CC BY-SA 4.0), which cites: Grove, A.T., "The Ancient Erg of Hausaland, and Similar Formations on the South Side of the Sahara", The Geographical Journal, 2007, p. 528–533; Bisson, J., "Mythes et réalités d'un désert convoité: le Sahara", L'Harmattan, 2003; Walton, K., "The Arid Zones", Aldine, 2007 (original not read by us) en.wikipedia.org
Wikipedia, "Sahara" (CC BY-SA 4.0), which cites: Chu, "A "pacemaker" for North African climate", MIT News, 2 January 2019 (we also read that source) en.wikipedia.org
Chu, "A "pacemaker" for North African climate", MIT News, 2 January 2019. facts only, no text reused. news.mit.edu
Wikipedia, "Sahara" (CC BY-SA 4.0), which cites: "Sahara's Abrupt Desertification Started By Changes In Earth's Orbit, Accelerated By Atmospheric And Vegetation Feedbacks", ScienceDaily, 12 July 1999; Kröpelin, "Climate-Driven Ecosystem Succession in the Sahara: The Past 6000 Years", Science, 2008, p. 765–768; White, "Ancient Lakes of the Sahara", American Scientist, 2006, p. 58–65 (we also read that source) en.wikipedia.org
"Sahara's Abrupt Desertification Started By Changes In Earth's Orbit, Accelerated By Atmospheric And Vegetation Feedbacks", ScienceDaily, 12 July 1999. facts only, no text reused. sciencedaily.com
"Largest Desert in the World". facts only, no text reused. geology.com
"The 10 Largest Deserts In The World", WorldAtlas, 13 October 2020. facts only, no text reused. worldatlas.com

Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Sahara (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.