Botswana–Namibia border

Lines on an 1890 map

In 1890 Britain and Germany negotiated their spheres of influence across Africa. In the southwest, Britain wanted to protect trade routes running north through Lake Ngami to Victoria Falls, and Germany, which already claimed much of South West Africa, wanted British recognition of its access to the Zambezi. The resulting treaty of 1 July 1890 also swapped the island of Heligoland to Germany in exchange for Zanzibar.^[1]

Article III of the treaty drew the line that still divides the two countries. From the Orange river it follows the 20th meridian east north to the 22nd parallel south, runs east to the 21st meridian, follows that north to the 18th parallel, then runs east to the Chobe river and down its main channel to the Zambezi.^[1] The strip of land it gave Germany along the Chobe is called the Caprivi Strip, after the German chancellor who concluded the treaty.^[1]

“It is understood that under this arrangement Germany shall have free access from her Protectorate to the Zambesi by a strip of territory which shall at no point be less than 20 English miles in width.”^[1]

A century of changing rulers

When World War I began in 1914, British forces from Southern Rhodesia occupied the Caprivi Strip. From 1919 South Africa ran South West Africa under a League of Nations mandate, and from 1921 to 1929 it handed the Caprivi Strip to the British Bechuanaland Protectorate to administer.^[1]

Bechuanaland became independent as Botswana on 30 September 1966. The UN General Assembly ended South Africa’s mandate the same year, but South Africa kept control of the territory until Namibia’s independence on 21 March 1990.^[1]

Kasikili or Sedudu?

The Chobe splits around an island of about 3.5 km² that floods for several months a year from around March. Namibians call it Kasikili and people in Botswana call it Sedudu.^[2] Its southern bank in Botswana is part of the Chobe National Park.^[1]

Soon after Namibia’s independence the two countries disagreed over which channel was the treaty’s “main channel”. Botswana said it was the northern one, which would put the island in Botswana; Namibia said it was the southern one.^[2] Zimbabwe’s president brought the three leaders together at Kasane in May 1992, and a joint team of technical experts surveyed the river from 1993 to 1994 but could not agree. In 1996 Botswana and Namibia sent the case to the International Court of Justice.^[1]

On 13 December 1999 the court ruled, by eleven votes to four, that the border follows the deepest line of the northern channel and that the island belongs to Botswana. It measured the channels by depth, width, flow and navigability. It also rejected Namibia’s other argument: that the Masubia of the Caprivi Strip, who had farmed the island for many years, gave Namibia title to it. The court found they used it seasonally for farming, not as an arm of the state.^[2]

The court added, unanimously, that boats and people of both countries should be treated equally in both channels around the island, as the two sides had already promised each other at Kasane in 1992.^[2]