Physical Geography

Most of the Congo lies in the Congo Basin, a large, saucer-shaped depression that extends into the Republic of the Congo and the Central African Republic. The basin lies at an average elevation of 1,300 feet (400 m) above sea level and is covered by one of the world's largest tropical rain forests, a luxuriant growth of trees, shrubs, and vines. Plateaus and uplands rim the basin in the north, east, and south; along the Congo's eastern boundary they rise to form mountains. The plateaus and uplands are relatively narrow on the north and east but widen in the south to cover about a third of the country. This upland terrain varies in elevation from about 2,000 to 5,000 feet (600 to 1,500 m). It consists chiefly of rolling savannas.

The mountains of eastern Congo include several forested ranges that are flanked on the east by the Great Rift Valley. Elevations increase from nearly 10,000 feet (3,000 m) in the Mitumba Mountains in the south to 16,763 feet (5,109 m) at Margherita Peak, the summit of the Ruwenzori range on the Uganda border.

The Congo is drained by the vast Congo River system, including such major tributaries as the Lomami, Aruwimi, Ubangi, and Kwa rivers. The Congo River crosses the country in a giant arc from headwaters in the southeast and empties into the Atlantic Ocean at the Congo-Angola border. Its upper course, above Boyoma Falls, is called the Lualaba Hydroelectric installations on the Congo River generate most of the nation's electricity.

Some of Africa's largest natural lakes—Tanganyika, Albert, Mweru, Kivu, and Edward—lie in the Great Rift Valley on the Congo's eastern border Other sizable lakes include Tumba and Mai-Ndombe, in the Congo Basin, and Upemba and Retenue, in the southeast.

The Congo Basin has a tropical rainy climate, with temperatures near 80° F (27° C.) and high humidity the year round. Rainfall totals 60 to 80 inches (1.520 to 2,030 mm) annually and occurs throughout the year On the plateaus away from the Equator, a tropical savanna type of climate emerges, with alternate wet and dry seasons and an annual rainfall of 40 to 60 inches (1,015 to 1,520 mm). The rainy season usually lasts from April to November in the north and from October to May in the south. Except where elevations exceed 4,000 feet (1,200 m)—mainly in the southeast—temperatures are similar to those in the Congo Basin, with slightly greater seasonal and daily variations. In the mountains climate is determined largely by elevation.