Zambia tributaries rise in Angola's central highlands. The edge of the Cuando River floodplain (not its main channel) forms Zambia's southwestern border, and via the Chobe River that river contributes very little water to the Zambezi because most is lost by evaporation. Two of the Zambezi's longest and largest tributaries, the Kafue and the Luangwa, flow mainly in Zambia. Their confluences with the Zambezi are on the border with Zimbabwe at Chirundu and Luangwa town respectively. Before its confluence, the Luangwa River forms part of Zambia's border with Mozambique. From Luangwa town, the Zambezi leaves Zambia and flows into Mozambique, and
British South Africa Company Zimbabwe, and North-Eastern Rhodesia (now part of Zambia) and Portuguese Mozambique. It divided Manica, granting the western portion to the British South Africa Company. It also fixed the boundaries between the BSAC-administered territory of North-Western Rhodesia (now in Zambia), and Portuguese Angola. The northern border of the British territories was agreed as part of an Anglo-German Convention in 1890. The border between the British Central Africa Protectorate and the territory of the British South Africa Company in what is today Zambia was fixed in 1891 at the drainage divide between Lake Malawi and the Luangwa River. The terms of the