Most people picture a desert as an ocean of sand under a blazing sun. But geographers define a desert by aridity — a place that receives very little precipitation, usually under 250 mm a year. By that definition, the largest deserts on the planet are the bitterly cold polar deserts of Antarctica and the Arctic.
Here are the world’s largest deserts, including both the frozen giants and the famous hot deserts.
The largest deserts, ranked
| Desert | Type | Approx. area | Location |
|---|---|---|---|
| Antarctic Desert | Polar (cold) | 14.0 million km² | Antarctica |
| Arctic Desert | Polar (cold) | 13.9 million km² | Arctic region |
| Sahara | Subtropical (hot) | 9.2 million km² | North Africa |
| Arabian Desert | Subtropical (hot) | 2.3 million km² | Arabian Peninsula |
| Gobi Desert | Cold winter | 1.3 million km² | China & Mongolia |
| Kalahari Desert | Subtropical | 0.9 million km² | Southern Africa |
The frozen giants
Antarctica is the largest desert on Earth. Despite being buried under kilometres of ice, it receives almost no precipitation — the interior gets less than 50 mm a year, drier than much of the Sahara. The Arctic desert ranks a close second. Both are classed as polar deserts because they are defined by extreme aridity, not temperature.
The Sahara: the largest hot desert
The Sahara is the largest hot desert in the world, stretching across North Africa at roughly 9.2 million square kilometres — about the size of the United States or China. Contrary to the postcard image, only around a quarter of it is sand dunes; the rest is gravel plains, rocky plateaus and bare mountains. Daytime summer temperatures regularly exceed 45°C, yet nights can plunge near freezing.
Hot deserts vs. cold deserts
Hot deserts such as the Sahara and Arabian are found near the tropics, where descending dry air prevents rain. Cold deserts such as the Gobi and the polar deserts are either high in latitude or altitude, or sit in the “rain shadow” behind mountain ranges that wring the moisture out of the air before it arrives.
Frequently asked questions
What is the largest desert in the world?
The Antarctic Desert is the largest desert on Earth at about 14 million square kilometres. Because a desert is defined by low precipitation rather than heat, the frozen, nearly rainless continent of Antarctica qualifies as the biggest.
What is the largest hot desert?
The Sahara in North Africa is the largest hot desert, covering roughly 9.2 million square kilometres — comparable in size to the United States or China.
Why is Antarctica considered a desert?
A desert is defined by how little precipitation it receives, not by temperature. The interior of Antarctica gets less than 50 mm of precipitation a year, making it one of the driest places on Earth and a true polar desert.
What is the difference between a hot and a cold desert?
Hot deserts lie near the tropics where sinking dry air suppresses rain, like the Sahara. Cold deserts occur at high latitudes or altitudes, or in the rain shadow of mountains, like the Gobi and the polar deserts.