Nzwani, also known as Anjouan, has been called the "pearl" of the Indian Ocean. It is a triangular island rising to a volcanic peak at Mount Ntingui, which reaches an elevation of about 1,580 metres(5,200 feet).

Nzwani has a total area of 424 square kilometers (164 square miles) and a population of more than 210,000 people, making it is the most densely populated island in the Comoro archipelago. The main towns are Mutsamudu and Domoni. Mutsamudu lies on the northwest coast, is the present capital of Nzwani and the site of an artificial harbor. Moroni on Ngazidja has the other artificial harbor, from which almost all freight is carried out by sea.

Its popualtiion is around 20,000. Domoni on the eastern shore is an ancient capital and seaport. Other ancient communities are Sima and Ouani. The island has no natural harbors.

Mount Ntingi, 1,575 meters high, is covered with vegetation; large ferns, tropical mahoganies, and wild orchids, in contrast with the three points of the triangle, which have been over cultivated, leading to erosion.

Nzwani is the main producer of ylang-ylang, jasmine, cassis, basilic, palmarosa, and orange flower oils.