Tanzania , officially the United Republic of Tanzania (Swahili: Jamhuri ya Muungano wa Tanzania), is a sovereign state in eastern Africa within the African Great Lakes region. It borders Kenya and Uganda to the north; Rwanda, Burundi, and the Democratic Republic of the Congo to the west; Zambia, Malawi, and Mozambique to the south; and the Indian Ocean to the east. Mount Kilimanjaro, Africa's highest mountain, is in north-eastern Tanzania.

The United Nations estimated Tanzania's 2016 population at 55.57 million.The population is composed of several ethnic, linguistic, and religious groups. Tanzania is a presidential constitutional republic and since 1996 its official capital city has been Dodoma where the president's office, the National Assembly, and some government ministries are located.Dar es Salaam, the former capital, retains most government offices and is the country's largest city, principal port, and leading commercial centre.

Tanzania is mountainous and densely forested in the north-east, where Mount Kilimanjaro is located. Three of Africa's Great Lakes are partly within Tanzania. To the north and west lie Lake Victoria, Africa's largest lake, and Lake Tanganyika, the continent's deepest lake, known for its unique species of fish. The eastern shore is hot and humid, with the Zanzibar Archipelago just offshore. The Kalambo water falls in the southwestern region of Rukwa are the second highest uninterrupted fall in Africa and are located near the south-eastern shore of Lake Tanganyika on the border with Zambia.The Menai Bay Conservation Area is Zanzibar's largest marine protected area.