Why Zambia is shaped like a butterfly

A company’s territory north of the Zambezi

In 1888 Britain proclaimed the land that became Northern Rhodesia to be in its sphere of influence.^[5] A Foreign Office paper of 13 February 1891 extended the British South Africa Company’s operations north of the Zambezi, but drew a western limit that kept the company out of Nyasaland, now Malawi. A second paper of 14 May 1891 set that same limit as Nyasaland’s western border. It follows the drainage divide: rivers to the east flow into Lake Nyasa, and rivers to the west flow to the Zambezi.^[7]

The company’s lands on both sides of the river were named Rhodesia in 1895. North of the Zambezi, Orders in Council of 1899 and 1900 set up two territories, Barotziland–North-Western Rhodesia and North-Eastern Rhodesia, and in 1911 they were combined as Northern Rhodesia.^[1] The Colonial Office took over its administration in 1924.^[5]

Other powers fixed the rest of the edges. An Anglo-German agreement of 1 July 1890 drew the line with German East Africa, now Tanzania, between Lakes Nyasa and Tanganyika.^[8] An Anglo-Portuguese treaty of 11 June 1891 drew the line with Mozambique, down the Luangwa river to the Zambezi.^[1]

The Congo Pedicle

In the north, Britain and King Leopold II, ruler of the Congo Free State, signed an agreement at Brussels on 12 May 1894. Its line ran from Cape Akalunga on Lake Tanganyika to Lake Mweru, then up the Luapula river to where it leaves Lake Bangweulu. From there it ran due south along a meridian to the watershed between the Congo and the Zambezi, and followed that watershed to the Portuguese frontier.^[2]

The Luapula and the watershed do not meet, and the land in the gap between them is the Congo Pedicle. Leopold’s agents had hoped to push their claims all the way to the fish and game of the Bangweulu basin, but the lake stayed British.^[3] The result is a long Congolese salient, which Belgium later let Britain build a road across.^[3]

The Pedicle splits Zambia into two lobes of roughly equal size. Crossing it is the easy way between the north-east and the centre of the country, and going around it is hard because the Bangweulu wetlands are in the way.^[3] That unpaved road was built after the Second World War. When Congolese border guards went unpaid in the 1970s and began extorting money from Zambian traffic, Zambia built the 300 km Samfya–Serenje road around the Pedicle, with nearly 20 km of causeways across the wetlands. It was finished in 1983.^[3]

“It shall then follow the “thalweg” of the Luapula up to its issue from Lake Bangweolo. Thence it shall run southwards along the meridian of longitude of the point where the river leaves the lake to the watershed between the Congo and Zambesi, which it shall follow until it reaches the Portuguese frontier.”^[2]

Barotseland and the King of Italy

The 1891 Anglo-Portuguese treaty left the Barotse Kingdom in the British sphere, but said its western limits, which would be the border with Portuguese Angola, were to be decided by a joint commission.^[4][5] A temporary line along the Zambezi and the Kabompo river held from 1893.^[5] On 12 August 1903 the two governments asked the King of Italy to decide, defining the kingdom as the land over which the King of Barotse was paramount ruler on 11 June 1891.^[4]

Victor Emmanuel III gave his award in Rome on 30 May 1905. He held that paying tribute did not prove that a people was ruled by King Lewanika, and found, for example, that the Balovale, as the award calls them, were still independent in June 1891. He also found that no precise line was possible: there were no separating natural features, the land was poorly known and its communities moved often. So where natural lines were missing, he used lines of latitude and longitude.^[4]

His line ran from the Katima rapids on the Zambezi towards Andara on the Okavango as far as the Kwando river, up the eastern edge of the Kwando’s high-water bed to the 22nd meridian, north along that meridian to the 13th parallel, east along the parallel to the 24th meridian, and north along it to the Congo Free State.^[4] That moved the southern part of the border west from the Zambezi to the Kwando. A 1915 protocol marked the northern part, with small departures from the 24th meridian to follow streams, and a convention of 18 November 1954 settled what the award’s French phrase about the Kwando’s high water meant.^[5]

“Le 22e méridien est de Greenwich jusqu’au point d’intersection avec le 13e parallèle; Le 13e parallèle jusqu’au point d’intersection avec le 24e méridien est de Greenwich; Le 24e méridien est de Greenwich jusqu’à la frontière de l’Etat Indépendant du Congo.”^[4]

The southern edge: Caprivi and the Zambezi

In the south-west, Zambia meets Namibia’s Caprivi Strip. A German–Portuguese declaration of 30 December 1886 ran a straight line east from Andara to the Katima rapids, and an Anglo-German agreement of 1 July 1890 extended German South West Africa to the Zambezi by a narrow corridor below that line. Today the Namibia–Zambia border is a straight line of about 55 miles from the Kwando to the Katima Mulilo rapids, then the Zambezi down to where the Linyanti joins it.^[9]

Just downstream, at Kazungula, Zambia touches Botswana for only about 150 metres of river, between two tripoints: one with Namibia and one with Zimbabwe. A 923-metre bridge across that short border opened on 10 May 2021.^[10]

From there to Mozambique the border with Zimbabwe, the former Southern Rhodesia, runs entirely in the Zambezi for 495 miles. It was set in 1895 as Hunter’s Road to the Zambezi and then the river. The Kariba Dam, whose first stage was completed during the Federation of Rhodesia and Nyasaland, created a reservoir 160 miles long that covered the old line. An Order in Council effective 1 January 1964 replaced that stretch with straight lines through the lake, and put Livingstone Island, at the Victoria Falls, in Northern Rhodesia.^[6] The line reaches Mozambique where the Luangwa joins the Zambezi.^[1]

From colony to country

From 1 August 1953 to 31 December 1963 Northern Rhodesia was part of the Federation of Rhodesia and Nyasaland, and on 24 October 1964 it became independent as the Republic of Zambia.^[5] Some details were still loose: in 1965 the US Geographer noted Belgian and Northern Rhodesian maps that put the end of the Congo line on Lake Tanganyika about five miles apart.^[8]