How Many States Are in Tanzania? How the Map of 31 Regions Was Drawn

Tanzania has no states. It is a unitary republic divided into 31 regions (mikoa in Swahili, singular mkoa): 26 on the mainland and 5 in the semi-autonomous Zanzibar archipelago, three on Unguja and two on Pemba. The regions are split into 184 districts (wilaya). The largest region is Tabora at 76,151 km², the most populous is Dar es Salaam with 5,383,728 people at the 2022 census, and the smallest is Mjini Magharibi (Zanzibar Urban West) at 230 km², home to Zanzibar City. The national capital, Dodoma, is the seat of Dodoma Region in the centre of the country. The total has stood at 31 since Songwe Region was created on 29 January 2016. That figure is the end point of six decades of splitting and renaming that started with a handful of colonial provinces.

German East Africa and Britain’s provinces, 1885 to 1961

The mainland's internal borders began as colonial ones. Germany claimed the territory in 1885 under an imperial charter and ran it as German East Africa, with its first capital, from 1886 to 1891, at Bagamoyo on the coast north of Dar es Salaam. After the First World War Britain took over the territory as Tanganyika and organised it into large provinces. Names from that period still explain today's map. The Northern Province covered the districts around Arusha and Mbulu and the slopes of Kilimanjaro. Pare District, now in Kilimanjaro Region, belonged to Tanga Province. The Lake Province stretched along Lake Victoria and inland, taking in the country that is now Kagera, Geita, Mwanza, Shinyanga, Tabora, Simiyu and Mara regions.

The colonial governments also kept returning to the idea of a central capital. Germany considered the Dodoma area for a new seat of government as early as 1915, and the British looked at it again in 1932, when Tanganyika was a League of Nations mandate. Neither moved, and Dar es Salaam stayed the capital through to independence on 9 December 1961.

Lake Region, West Lake and Kilimanjaro: the regions of 1963

Independence brought a change of vocabulary and then a change of scale. The Lake Province became the Lake Region, and within two years it was broken up. In 1963 Mwanza Region was created around the lake port that the Germans had founded in 1892. After the break-up, the western shore of Lake Victoria, together with part of what is now Geita, became West Lake Region, governed from Bukoba. Out of the old Northern Province came Kilimanjaro Region, formally established in 1963 with just two districts, Kilimanjaro and Pare, and its seat at Moshi. It contains Mount Kilimanjaro, at 5,895 m the highest point in Africa, and today has six districts and 1,861,934 residents (2022).

The new regions were smaller and more numerous than the provinces they replaced. Each is headed by a regional commissioner, a post whose list of holders in Mwanza begins with Richard Saimora Wambura, from 1961 to 1963, and each is divided into districts run by district councils, with cities administered by their own councils.

Zanzibar’s five regions and the union of 26 April 1964

The island regions have a separate history. Zanzibar became independent from Britain in December 1963 as a sultanate, and on 12 January 1964 Sultan Jamshid bin Abdullah was overthrown in the Zanzibar Revolution. Arab and Indian civilians were massacred, and estimates of the death toll range from several hundred to 20,000; around 10,000 people fled the island. On 26 April 1964 the new People's Republic of Zanzibar merged with Tanganyika, and on 29 October that year the joint state was renamed the United Republic of Tanzania, "Tan" from Tanganyika and "Zan" from Zanzibar.

Zanzibar kept its own Revolutionary Government, with a President (currently Hussein Mwinyi), a Revolutionary Council and a House of Representatives, and its own internal divisions. Unguja has three regions: Mjini Magharibi, which contains Zanzibar City and its historic centre, Stone Town; Unguja North, governed from Mkokotoni; and Unguja South, governed from Koani. Pemba has two: Pemba North, with its seat at Wete, and Pemba South, at Chake-Chake. Together the five regions had 1,889,773 residents in 2022. Mjini Magharibi alone held 893,169 on 230 km², making it the most densely settled region in the country.

Mtwara, Rukwa and the 25 regions of 1975

The 1970s added two more southern and western regions. Mtwara, on the Ruvuma River border with Mozambique, was part of Lindi Region until 1971, when it became a region of its own. Rukwa followed in 1975, created by President Julius Nyerere and named after Lake Rukwa. It was assembled from pieces of two older regions: Mpanda District, taken from Tabora Region, and the then unified Sumbawanga District, taken from Mbeya Region. Sumbawanga became its capital, and Nkasi District was later added in 1984. By 1975 Tanzania had 25 regions.

Two other decisions of the decade reshaped what the regions meant. In 1974 the government announced that the national capital would move from Dar es Salaam to Dodoma, in the geographic centre of the country. The site had been debated in the National Assembly in 1961 and 1966. It was chosen because the town already stood at a major crossroads, had room to grow and lay in the rural heartland of the ujamaa village policy. A Capital Development Authority then invited Canadian, Greek and Japanese planning firms to propose master plans. Dodoma became the official capital in 1996, although the move was slow, and the new State House there was only unveiled in 2023. Dar es Salaam remains the commercial capital and largest city.

The second change came from war. In October 1978 the Uganda Army invaded the Kagera Salient, about 1,900 km² of Tanzanian land between the border and the Kagera River, and Ugandan media declared it annexed. On 2 November Julius Nyerere declared war, and the Uganda–Tanzania War, known in Tanzania as the Kagera War, ended with the fall of Idi Amin in 1979. Following the war, West Lake Region was renamed Kagera Region.

Manyara in 2002 and the four regions of March 2012

The count then held at 25 for more than two decades. In 2002 Manyara Region was created out of Arusha Region, taking in the former Arusha districts of Kiteto, Babati, Mbulu and Hanang and a sliver of Monduli, with its capital at Babati. That made 26, and it ended Arusha's run, from 1966 to 2002, as the largest region in the country.

The largest single redraw came in March 2012, when four regions were created at once, three in the north and west of the country and one in the Southern Highlands:

• Geita, in the north-west on the shores of Lake Victoria, assembled from parts of Shinyanga, Kagera and Mwanza regions, with five districts. It had 2,977,608 residents by 2022.
• Simiyu, carved from Shinyanga Region, with its capital at Bariadi and 2,140,497 residents in 2022.
• Njombe, split from Iringa Region in the Southern Highlands, bordering Lake Nyasa, with its capital at Njombe town.
• Katavi, formed when Mpanda District left Rukwa Region, governed from Mpanda and named after Katavi, a spirit of Lake Tanganyika. It covers 45,843 km² and includes Katavi National Park.

So the Lake Province of the British era now accounts for seven regions, and the Mpanda country moved twice: from Tabora to Rukwa in 1975 and from Rukwa to Katavi in 2012.

Songwe, 29 January 2016, and the 31 regions today

The last change so far came on 29 January 2016, when Songwe Region was created from the western half of Mbeya Region, with its capital at Vwawa. That brought the total to 31, where it remains. Songwe covers 27,656 km² and had 1,344,687 people in 2022.

The result is a map of very uneven units. Tabora, in the west-central plateau, is the largest at 76,151 km², followed by Morogoro (70,624 km²) and Lindi (66,669 km²). At the other end, the five Zanzibar regions together cover less than 2,500 km². Population is just as lopsided: Dar es Salaam Region packs 5,383,728 people into 1,393 km², while Njombe on the mainland has fewer than 890,000. Tanzania's total at the 2022 census was 61,741,120.

Each new region has also produced a new regional capital, which is why towns such as Babati, Bariadi, Mpanda, Njombe and Vwawa now sit alongside older seats like Tabora, Bukoba and Moshi on the map. For how the regional commissioners fit under the President and the National Assembly in Dodoma, see our guide to the government of Tanzania; for the city at the centre of the 1974 decision, read about Dodoma, the capital of Tanzania; and to see how a neighbour drew its own map, compare Tanzania's regions with Kenya's 47 counties.