German East Africa, bounded on the east by the Indian Ocean, stretches from 1º to nearly 12º south, and from 29º 30′ to 40º 15′ east. Its sea coast is 620 m. long. The total area is given officially as 363,270 sq. m. The coast is low-lying and monotonous. Behind it is a hill-land, which merges westwards into higher and more plateau-like country. Thin forest is widespread, and, in general, there is a preponderance of pastoral and arable land. The mountain mass guarding the north frontier is 1,455 sq. m. in area, and culminates in Mt. Kilimanjaro (19,680 ft.). The Livingstone Range, nearly 10,000 ft. in height, rounds Lake Nyasa on its north and east sides. To the west lies the hilly table-land of Unyamwezi, including the populous Unyanyembe. The east drainage includes the rivers Pangani, Wami and Kingani, Rufiji (navigable 124 m. for four months of the year), Umbekuru, and Rovuma. The west drainage includes the Simiyu and Kagera (ultimate caput Nili), draining into Victoria Nyanza; the Malagarazi into Tanganyika; the Songwe into Rikwa; the Ruhuhu into Nyasa.
On Victoria Nyanza the maximum temperature is 88º, the mimmum 50º. In the interior the temperature ranges from 113º to 46º. The rainfall varies from 50 in. at Pangani to over 100 in. at Kwankoro. On the coast grow the mangrove, baobab, and tamarind. Thick forests of sweet apples, tamarinds, and melons crown the highlands. Coffee grows wild. Sorghum, maize, and bananas are cultivated in the interior; manioc, coco-palms, vanilla, tobacco, india-rubber, and batatas on the coast. The population is mostly Bantu; along the coast are Arabs, Baluchis, Indians, Goanese, Syrians, and Swahilis. The Swahili tongue is the lingua franca of East Central Africa. For centuries the interior has been subject to Arab influence from the coast, Zulu forays from the south, and Nilotic Negro and Hamitic encroachments from the north. July 1905 saw the beginning of a serious native rising which was only quelled in January 1907.
The principal port on the east coast is Dar-es-Salaam. Exports in 1910 were valued at £1,734,000, and imports at £2,217,000. The exports consist chiefly of rubber, sisal fibre, copra, ivory, coffee, and wax. The colony is administered by an imperial governor. In 1912 there were over 220 m. of railways open, and another 240 m. were under construction. In 1910 the native and non-European population was estimated at 10,000,000; the European population numbered 3,756.
Under Vasco da Gama the Portuguese began in 1498 to reduce the coast towns, but in 1698 the imam of Muscat dislodged the Europeans. In 1884 Dr. Peters, the German emissary, claimed treaty rights over Uzeguha, Ukami, Usagara, and Uguru – rights straightway enforced (1885) by imperial protection. The present boundaries were successively determined by agreement with the Congo Free State (1885), with Portugal (1886), with Great Britain (1886, 1890, and 1906). In 1890, in consideration of an indemnity of £200,000, the sultan of Zanzibar waived all his sovereign rights over the mainland and the island of Mafia in favour of Germany.