How many million years old is the Namib Desert, the world's oldest desert?

The Namib Desert is commonly described as about 55 million years old, making it one of the oldest—and often the oldest—deserts on Earth. The figure refers to the persistence of arid or semi-arid conditions in the region, rather than the age of every sand dune or rock within it.

The Namib stretches along the Atlantic coast of southern Africa, chiefly through Namibia and into parts of Angola and South Africa. Its extreme dryness is driven partly by the cold Benguela Current, which cools moist air and helps produce coastal fog without much rainfall. Some areas receive only a few millimetres of rain annually.

The exact age is not perfectly fixed: scientific and reference sources often give a range of roughly 55 to 80 million years, depending on how “desert” and continuous aridity are defined. That is why 55 million years is the standard quiz answer, even though the geological history is more nuanced. The Atacama Desert is another exceptionally old and arid desert, so “oldest” should be treated as a conventional description rather than an absolute uncontested ranking.