The Usambara's are a part of the ancient Eastern Arc chain which mountains stretch in a broken crescent from the Taita hills in southern Kenya down to Morogoro and the southern highlands. They are estimated to be at least 100 million years old and the rocks forming them may be as much as 600 million years old. The mountains are home to an exceptional assortment of plants and animals and represent one of the highest degrees of biodiversity on the continent.
The range is accessible from the towns of Lushoto in the west, and Amani in the east. The Usambaras are commonly split into two sub-ranges, the West Usambara and the East Usambara. The East Usambara is closer to the coast, receives more rainfall, and is significantly smaller than the west.
The East Usambara Mountains belong to Eastern Arc Mountains, which is a chain of isolated mountains stretching in a great arc from Southeast Kenya to Southwest Tanzania. Geologically the mountains are very old - at least 100 million years. The total area of African rain forests diminished due to cold and dry periods which started about 2.5 million years ago. The Indian Ocean maintained the moist climate required by the rain-forests. The individual Eastern Arc Mountains became isolated from the large African rain-forests and finally from each other.
The natural vegetation of submontane forest supports a wide variety of flora and fauna, much of which is endemic and for which the area is renowned both nationally and internationally. It is considered an international ‘hot spot’ for bio-diversity. The East Usambaras are particularly well known for bird life, with over 350 recorded species. The Usambaras are a bird-watching paradise.