Antarctica is the world's largest desert by area, covering much of the Antarctic continent.
A desert is defined by very low precipitation, not by heat. Antarctica receives little rain or snow across much of its interior, so it qualifies as a polar desert even though it is covered by ice. Its ice sheet contains about 90% of the world's ice and roughly 60% of the planet's fresh water.
Antarctica covers about 14 million square kilometres, making it larger than Europe and Australia. Most of the continent is permanently ice-covered, with the thickest ice concentrated in East Antarctica. Coastal regions generally receive more snowfall than the high interior.
The Sahara is the world's largest hot desert, but it is smaller than Antarctica. Greenland is also a polar desert, although it is an island rather than a continent and has a smaller total area.