What is the largest island off the coast of Africa?

The largest island off the coast of Africa is Madagascar.

Madagascar lies in the Indian Ocean, approximately 400 kilometres east of Mozambique, separated from mainland Africa by the Mozambique Channel. Covering about 587,000 square kilometres, it is the world’s fourth-largest island, after Greenland, New Guinea, and Borneo. Its size makes it substantially larger than other African offshore islands such as Zanzibar, Bioko, and Socotra.

The island separated from the ancient supercontinent Gondwana over a very long geological history, eventually becoming isolated from Africa and other landmasses. That isolation produced extraordinary biodiversity: Madagascar is famous for lemurs, baobabs, chameleons, and many species found nowhere else on Earth. Several major ecosystems range from humid eastern rainforests to dry western forests and spiny vegetation in the south.

Madagascar is sometimes confused with an African coastal region because it is politically part of Africa, but it is not connected to the continent by land. It is an independent island country whose capital is Antananarivo. The nearby Comoros archipelago and Mascarene islands are also offshore, but none approaches Madagascar in area.