Zambia is a landlocked country in southern Africa, with a tropical climate and consists mostly of high plateau, with some hills and mountains, dissected by river valleys. At 752,614 km2 (290,586 sq mi) it is the 39th-largest country in the world (after Chile) and slightly larger than the US state of Texas. The country lies mostly between latitudes 8° and 18°S, and longitudes 22° and 34°E.
Zambia is drained by two major river basins: the Zambezi/Kafue basin in the centre, west and south covering about three-quarters of the country; and the Congo basin in the north covering about one-quarter of the country. A very small area in the northeast forms part of the internal drainage basin of Lake Rukwa in Tanzania.
In the Zambezi basin, there are a number of major rivers flowing wholly or partially through Zambia: the Kabompo, Lungwebungu, Kafue, Luangwa, and the Zambezi itself, which flows through the country in the west and then forms its southern border with Namibia, Botswana and Zimbabwe. Its source is in Zambia but it diverts into Angola, and a number of its 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 eventually into the Mozambique Channel.
The Zambezi falls about 100 metres (328 ft) over the 1.6 km (0.99 mi) wide Victoria Falls, located in the south-west corner of the country, subsequently flowing into Lake Kariba. The Zambezi valley, running along the southern border, is both deep and wide. From Lake Kariba going east it is formed by grabens and like the Luangwa, Mweru-Luapula, Mweru-wa-Ntipa and Lake Tanganyika valleys, is a rift valley.