What Is the Largest Desert in the World?

Ask someone to name the largest desert in the world, and chances are they’ll answer “the Sahara.” It’s a common assumption – after all, the Sahara Desert in Africa is enormous and iconic for its scorching dunes. However, the true holder of the “world’s largest desert” title lies somewhere much colder. In fact, the largest desert on Earth is Antarctica – a place many people don’t even realize is a desert.

The world’s largest desert is the Antarctic Desert in Antarctica, spanning about 5.5 million square miles (14.2 million square kilometers)​. That makes it roughly one-and-a-half times the size of the Sahara. How can a land of ice and snow be a desert? The answer comes down to precipitation. By definition, a desert is any region that receives very little rainfall (or other forms of moisture) each year​. Antarctica fits that definition: most of the continent sees barely any rain or snowfall, earning it the top spot as the world’s driest and largest desert.

What Counts as a Desert (It’s Not Just Sand and Heat)

When we think of deserts, we often picture endless sand dunes under a blazing sun. While hot, sandy deserts like the Sahara are the most famous, “desert” simply means an area that gets less than about 10 inches (25 cm) of precipitation a year​. Deserts aren’t defined by temperature or sand – they’re defined by dryness. In fact, deserts can be hot or cold, and they come in many forms:

• Hot deserts: These are the classic deserts (like the Sahara or Arabian Desert) with high temperatures and very low rainfall.

• Cold deserts: These include places like Antarctica or the Arctic regions, where it’s frigid but still extremely dry.

• Semi-arid and coastal deserts: Some deserts, like parts of the Atacama Desert in Chile or Namib Desert in Namibia, have milder temperatures or coastal fog but still get minimal rain.

Interestingly, deserts cover about one-fifth of Earth’s land area and are found on every continent​. And despite the common image of sand dunes, only around 20% of deserts are covered in sand​. Many deserts are primarily rock, gravel, or in the case of Antarctica, ice. What unites all deserts is how dry they are.

Antarctica – The World’s Largest (and Coldest) Desert

Antarctica is the coldest place on Earth and yet also its largest desert. 5.5 million sq mi (14.2 million sq km)​, making it the largest desert on the planet by far. How can a place covered in ice be so dry? The interior of Antarctica receives almost no rain at all – only about 2 centimeters (0.8 inches) of precipitation per year​on average, mostly as tiny ice crystals. That’s less moisture than the Sahara gets. In fact, huge portions of Antarctica haven’t seen rain in millions of years. One region, the McMurdo Dry Valleys, is so extreme that it’s the only known place on Earth with virtually no microbial life present​ – a testament to how harsh and dry Antarctica is.

Much of the precipitation that does fall in Antarctica never melts; it just accumulates as snow and compresses into ice over time. This continent holds about 90% of the world’s ice. Along the coasts, Antarctica does get a bit more snowfall (up to 8 inches or 200 mm of water equivalent per year in some areas)​, which allows penguins, seals, and other wildlife to survive there. But overall, the entire continent averages well under the threshold to be a desert. That’s why scientists unequivocally classify Antarctica as a desert – the world’s largest and coldest desert.

It’s also worth noting that Antarctica’s status as the largest desert might not be permanent. Climate change is causing polar ice to melt at unprecedented rates​. If Antarctica’s ice sheets retreat, its environment could change, potentially altering precipitation patterns over time. For now, though, Antarctica remains a frigid desert of ice, wind, and minimal snowfall.

The Sahara – The Largest Hot Desert on Earth

The Sahara is the quintessential desert landscape, known for its sand dunes and brutal heat. Covering about 3.5 million square miles (9.1 million square kilometers)​, the Sahara Desert in North Africa is the world’s largest hot desert. It’s the third-largest desert overall, after Antarctica and the Arctic. The Sahara spans across 11 countries in northern Africa, from the Atlantic coast to the Red Sea, dominating the landscape of the region with its vast, arid expanse. To put its size in perspective, the Sahara is almost as large as the entire United States!

The climate in the Sahara is extremely dry and scorching. On average, most of the Sahara receives less than 4 inches (10 cm) of rain per year, and huge central areas get almost no rain at all. Near the few coastal or mountain fringes, annual rainfall might reach 4–10 inches (10–25 cm) in a good year​. But in the heart of the Sahara, some places see barely a quarter-inch of rain annually​ (just a few millimeters). This makes the central Sahara as dry as many parts of Antarctica. Daytime temperatures are famously high as well – often above 100°F (38°C) – although nights can get surprisingly cool.

Despite these harsh conditions, the Sahara is not lifeless. It is home to resilient communities of people (such as nomadic herders), plus wildlife like camels, fennec foxes, and various reptiles that have adapted to the extreme environment. However, life clusters around oases and the edges of the desert where water can be found.

One alarming fact about the Sahara is that it’s growing. Scientists have found that the Sahara Desert has expanded by roughly 10% since 1920​, encroaching further into semi-arid regions. This expansion – a process called desertification – is driven by climate change and human activities like overgrazing. In short, the world’s biggest hot desert is getting even bigger over time.

Other Massive Deserts Around the Globe

While Antarctica and the Sahara hold the top spots, several other deserts deserve mention due to their vast size:

• Arctic Polar Desert (Arctic Regions): The Arctic region – spanning parts of northern Canada, Greenland, Russia, and Alaska – forms Earth’s second-largest desert. This cold Arctic Desert covers about 5.4 million sq mi (13.9 million sq km)​, just slightly smaller than Antarctica’s desert. Like Antarctica, the Arctic qualifies as a desert because of extremely low precipitation. Much of its moisture is locked up as snow and ice, and what snow does fall often never melts​.

• Arabian Desert (Middle East): Covering around 1 million sq mi (2.6 million sq km)​, the Arabian Desert dominates the Arabian Peninsula (including much of Saudi Arabia, Oman, Yemen, and surrounding areas). It’s the second-largest subtropical desert in the world, known for its oil-rich sands and hot, dry climate.

• Gobi Desert (East Asia): The Gobi Desert in northern China and Mongolia is about 500,000 sq mi (1.3 million sq km)​ in area. It’s a cold winter desert, meaning it has frigid winters. The Gobi’s landscape is a mix of bare rock and gravel plains with occasional dunes; it can even see snow at times.

• Kalahari Desert (Southern Africa): Spreading over roughly 360,000 sq mi (930,000 sq km) across Botswana, Namibia, and South Africa, the Kalahari is a semi-arid desert. Parts of it support scrubby vegetation and wildlife (like meerkats and springboks) during rare rains.

• Patagonian Desert (South America): Also known as the Patagonian Steppe, this cold, windy desert in Argentina and Chile spans about 260,000 sq mi (670,000 sq km). It’s the largest desert in the Americas, characterized by rocky soil and sparse rainfall due to the rain shadow of the Andes Mountains.

As these examples show, deserts come in different varieties across the world – from polar ice deserts to subtropical sand seas. What they all share is an environment of extreme dryness.

FAQs about the World’s Largest Desert

Q: Why is Antarctica considered a desert?

A: Antarctica is considered a desert because of its minuscule precipitation. Most of the continent receives less than 2 inches (5 cm) of snowfall (water equivalent) per year​, and some interior areas get almost no precipitation at all. Despite all the ice, Antarctica’s air is extremely dry – as cold air holds very little moisture. By definition, its low annual rainfall/snowfall qualifies Antarctica as a desert, just like the Sahara.

Q: What is the largest hot desert on Earth?

A: The largest hot desert in the world is the Sahara Desert in North Africa. It spans about 3.5 million square miles (9 million+ square kilometers)​, making it the size of a small continent. The Sahara is famous for its vast sand dunes and very high temperatures, unlike Antarctica’s cold desert climate.

Q: Are all deserts covered in sand dunes?

A: No. Only around 20% of the world’s deserts are covered in sand​. Many deserts are dominated by rocks, gravel, or salt flats. For example, much of the Sahara is actually bare rock and gravel plains rather than sand dunes. Likewise, polar deserts are covered in ice and snow. Deserts simply need to be dry – they don’t have to be sandy.

Q: Is the Sahara Desert expanding?

A: Yes, the Sahara has been slowly expanding over the past century. Research indicates the Sahara grew roughly 10% larger between 1920 and 2013​, extending its area further south and west. This expansion is linked to climate change (shifting weather patterns) as well as local factors like over-farming and deforestation, which can lead to land becoming drier (desertification).

Q: What is the driest desert in the world?

A: If we look at the driest place on Earth, one candidate is the Atacama Desert in Chile. Parts of the Atacama receive under 0.1 inches (2–3 millimeters) of rain per year​ – essentially none at all. Some weather stations in the Atacama have recorded zero rainfall for years. Even Antarctica’s interior, while extremely dry, has tiny amounts of snowfall; the Atacama’s core is often comparably arid. This makes the Atacama the driest hot desert. (Antarctica’s Dry Valleys are drier still, but they’re cold and covered in ice.)

Conclusion

It may come as a surprise, but the largest desert in the world is not a sea of sand – it’s a continent of ice. Antarctica’s frozen expanse holds the record due to its lack of precipitation, outclassing even the mighty Sahara in size and dryness. Understanding this fact reshapes how we think of deserts: they can be freezing cold or scorching hot, full of sand or covered in ice. What truly defines a desert is aridity. From the icy wilderness of Antarctica to the sun-baked dunes of the Sahara, Earth’s deserts are extreme environments that showcase the planet’s remarkable diversity. By appreciating these unique landscapes – and recognizing how factors like climate change can alter them – we gain a deeper respect for the fragility and wonder of our world’s ecosystems.