Unyamwezi is a historical region in what is now Tanzania, around the modern city of Tabora to the south of Lake Victoria and east of Lake Tanganyika. It lay on the trade route from the coast to Lake Tanganyika and to the kingdoms to the west of Lake Victoria. The various peoples of the region were known as long-distance traders, providing porters for caravans and arranging caravans in their own right. At first the main trade was in ivory, but later slaving became more important.
The Unyamwezi region lies around the modern town of Tabora, between the coast and Lake Tanganyika, and includes the Tabora, Nzega and Kahama districts of the western plateau of modern Tanzania. Unyamwezi is mentioned as early as the 16th century by the Portuguese and by Antonio Pigafetta, under the name Munemugi or " Land of the Moon," which is the exact equivalent of the name Wu-nya-mweziby which the land is known to its own people. The Encyclopædia Britannica Eleventh Edition said the region "is rich in woods and grass, and has many villages surrounded by well cultivated farms and gardens. The western portions, however, are somewhat swampy and unhealthy."
In the 19th century the inhabitants were called Nyamwezi people by outsiders, although this term covered various different groups.
Unyamwezi lay at a juncture where a trade route from the coast split, with one branch going west to the port of Ujiji on Lake Tanganyika while another branch led north to the kingdoms of Buganda and Bunyoro.
Coastal traders settled in Unyamwezi, some with hundreds of well-armed retainers. The Nyamwezi provided most of the porters for the caravans organized by the coastal Arabs and Swahilis, and also conducted their own caravans. The Nyamwezi were long-distance traders throughout East Africa.