Desert island

A desert island is an island where no people live. More commonly they are called uninhabited islands. Sometimes the name is also used for an islet or atoll. Very often, such places are seen as close to paradise. Most islands in the world are uninhabited.
The reason why an island is uninhabited are often practical:
They are too small
There may be no source of fresh water on the island
They may be in areas where there's a bad climate.
They are close to another bigger settlement. Living in the settlement is more attractive.
Humans did some tests on them. Because of tests of nuclear weapons, the Bikini atoll will not be a safe place to live for humans for thousands of years.
Among the biggest uninhabited islands:
Novaya Zemlya is made of two islands, which are separated by a narrow channel. There are about 2.500 people on the two islands, all of them live in two settlements on the south island. The north island has a size of roughly 

References

Category:Uninhabited islands