The ranges of approximately 90 kilometres (56 mi) long and about half that wide, are situated in the Lushoto District of the Tanga Region.

[2] The West and East Usambaras are large ranges of Precambrian metamorphic geologic formations of acid-gneisses, pyroxenes, and amphiboles.

There are many protected zones throughout the range, which are being expanded and contributed to by the Tanzanian government, associated NGO's and research teams, and donor countries such as Norway.

[5] Under Kinyashi's son Kimweri ye Nyumbai the kingdom grew to cover both the west and east Usambaras, extending down to the coast and into the Pangani River valley to the south.

[9][better source needed] The result of colonialism was a massive change in the way forests were perceived in the community, and conversion of traditional agriculture to cultivating cash crops such as quinine, pine trees, bananas, maize, tea, and coffee.

In 1882 Walter von Saint Paul-Illaire, the governor of the Usambara District of German East Africa, collected seeds of a small herb which he sent to his father, who cultivated them into plants.

Hermann Wendland, the director of the Herrenhausen Gardens, formally described the plants and recognized them as representing a new species in a new genus, Saintpaulia ionantha, with the English common name African violet.

[12][verification needed] Most of the inhabitants are subsistence farmers who rely heavily on the forests around them for timber, medicinal plants, clearing for agriculture, and fuelwood.

A sawmill at Tanga processed East Usambara timber, and its output was increased in the 1970s with Finnish development funding.