The largest island on Earth is Greenland, with a total land area of 2.2 million km2.
This is a bit of a complicated question because it’s hard to define the difference between an island and a continent. Both Antarctica and Australia are larger than Greenland, but they’re continents, so they’re out.
As you probably know, Greenland sits up near the Earth’s north pole, in between North America and Europe. More than 80% of the island is covered by glaciers, some of which can be more than a kilometer thick. With such an extreme environment, Greenland is sparsely populated; roughly 60,000 people live on the island, and most of those live in the capital city of Nuuk, on the southern island.
If you’re interested, the second largest island on Earth is New Guinea, with 785,000 square kilometers. And the third largest island is Borneo, with 748,000 km.
We have also recorded an episode of Astronomy Cast about Earth, as part of our tour through the Solar System – Episode 51: Earth.