How does the Sahara Desert shape Algeria’s geography?

The Sahara Desert is a defining feature of Algeria, occupying the vast majority of the country’s territory to the south of the Atlas Mountains. Its influence on the nation's geography and life is profound:8

• Physical Landscape: The Algerian Sahara is characterized by two massive depressions separated by the Mzab rise. These zones contain vast sand dune sheets known as ergs—the Great Eastern and Great Western Ergs—as well as the majestic Ahaggar Mountains, which include the country’s highest peak, Mount Tahat.1
• Climate and Environment: The desert dictates a harsh climate with extreme temperature fluctuations and minimal precipitation, often less than 4 inches (100 mm) annually. Seasonal sirocco winds emanate from the Sahara, carrying dust and desiccating air that impact agriculture and daily life even in northern regions.2
• Settlement and Demographics: Due to the extreme environment, large stretches of the Sahara are virtually uninhabited. Population density is highest in the northern coastal regions, while traditional nomadic lifestyles in the desert have declined significantly due to drought and government settlement policies.34
• Economic Impact: While the desert presents significant developmental challenges, it is a vital source of oil and natural gas reserves, which are central to Algeria’s economy.56