Liberia can be divided into three distinct topographical areas. First, a flat coastal plain of some 10 to 50 mi (16–80 km), with creeks, lagoons, and mangrove swamps; second, an area of broken, forested hills with altitudes from 600 to 1,200 ft (180–370 m), which covers most of the country; and third, an area of mountains in the northern highlands, with elevations reaching 4,540 ft (1,384 m) in the Nimba Mts. and 4,528 ft (1,380 m) in the Wutivi Mts. Liberia's six main rivers flow into the Atlantic. Vegetation in much of the country is dense forest growth. The climate is tropical and humid, with a heavy rainfall, averaging 183 in. (465 cm) on the coast and some 88 in. (224 cm) in the southeastern interior. There are two rainy seasons and a dry, harmattan season in December and January. In addition to the capital, other important towns include Buchanan and Harper, both ports.
The majority of the population belong to 16 ethnic groups, including the Kpelle, the Bassa, the Gio, the Kru, the Grebo, and the Mano. Traditional religions are practiced by about 40% of the people; another 40% are Christian, and 20% are Muslim. English is the official language, but is spoken by only about 20% of the people; African languages are used extensively. Far less numerous, but of great political importance in the past, are the descendants of freed slaves who immigrated from the United States to Liberia in the 19th cent. These people, formerly called Americo-Liberians, are concentrated in the towns, where they have provided the country's Westernized leadership and, for the most part, are adherents of various Protestant denominations. There are also communities of Lebanese merchants and European and American technicians.