The terrain consists of a 2,000–3,000 ft (610–910 m) undulating plateau, mainly covered by savanna; dense tropical forests in the south; and a semidesert area in the east. The Bongo Massif in the northeast reaches a height of c.4,500 ft (1,370 m). The country is drained by numerous rivers, but only the Ubangi is commercially navigable. Rainfall is heavy in the south; the north is hot, dry, and subject to harmattan winds. There are no railroads, and the network of all-weather roads is inadequate; rivers are the chief means of transportation.
The population consists of approximately 80 ethnic groups, including the Baya, Banda, Mandjia, Sara, Mboum, Mbaka, and Yakoma. There is a small European minority. Considerable migration of inhabitants from urban to rural areas has led to the uneven distribution of the population. Population density is low relative to other African nations, and the eastern portion of the republic is largely uninhabited. French is the official language, but Sango, the national tongue, is used as a lingua franca; Arabic, Hausa, and Swahili are also spoken. About 35% of the population practices traditional religions, 50% are Christian, and about 15% are Muslim.