Antarctica is the largest desert on Earth by area, according to geographic classification.
A desert is defined mainly by very low precipitation, not by heat. Antarctica receives little snowfall across its vast interior, making it a polar desert even though it is covered by ice. Its area is about 14 million square kilometres, larger than the Sahara.
The Sahara is the world’s largest hot desert, which is why it is often mistakenly named as Earth’s largest desert overall. Antarctica’s extreme cold also prevents much of its limited snowfall from melting, so ice accumulates over enormous timescales.
Antarctica contains roughly 90% of the world’s ice and about 70% of its fresh water. The continent’s dry valleys, especially the McMurdo Dry Valleys, are among the most desert-like regions on Earth, with exceptionally little precipitation and almost no permanent surface ice.