The third largest desert in the world, and the largest non-polar desert is the Sahara. Situated in North Africa, the Sahara makes up parts of Algeria, Chad, Egypt, Eritrea, Libya, Mali, Mauritania, Morocco, Niger, Sudan, Tunisia, and Western Sahara.he Kalahari Desert is a subtropical desert in southern Africa, covering 900,000 square kilometers in Angola, Botswana, Namibia, and South Africa. The Kalahari Desert ranks sixth in terms of largest deserts by area in the world.