Which desert is the largest desert on Earth, covering most of Antarctica?

The Antarctic Desert is the largest desert on Earth, covering most of Antarctica.

A desert is defined by very low precipitation, not by heat. Antarctica receives so little snowfall and rainfall across its vast interior that it qualifies as a desert, despite being covered by ice. The Antarctic Desert covers about 13.8 million square kilometres when the continent’s ice sheet is included.

The interior is exceptionally cold, dry, and windy. The East Antarctic Ice Sheet contains the vast majority of the continent’s ice and reaches several kilometres in thickness in places. Coastal areas can receive more snow than the high interior, but much of the continent remains polar desert.

Antarctica also contains the McMurdo Dry Valleys, where strong katabatic winds remove snow and moisture. These valleys are among the driest places on Earth and expose bare rock and soil, offering scientists an analogue for some Martian environments.