On Earth, which desert is the world's largest by area?

The Antarctic Desert is the world's largest desert by area.

A desert is defined by very low precipitation, not by heat. Antarctica receives little snowfall or rain across most of its vast ice-covered interior, so it qualifies as a polar desert. Its frozen surface can make the region seem unlike the hot deserts more familiar from maps and photographs.

The Antarctic Desert covers the Antarctic continent and surrounding polar environments, making it much larger than the Sahara. The Sahara is the world's largest hot desert, but it is not the largest desert overall. Antarctica's extreme cold also keeps much of its limited moisture locked as ice.

Antarctica is surrounded by the Southern Ocean and has no permanent native human population. Scientific stations operate there under the Antarctic Treaty System, while the continent's ice sheet stores most of Earth's fresh water.