Much of Sierra Leone's coastline consists of mangrove swamps, with the exception of the peninsula on which the capital city Freetown is located.

The rest of Sierra Leone is mostly plateau (about 300 m or 1,000 ft above sea level) covered by forests, with mountains in the northeast of the country (highest point Loma Mansa, 1,948 m; 6,391 ft).

The climate is tropical, with a rainy season from May to December.

Major cities are the capital Freetown, Koidu (Sefadu), Bo, Kenema and Makeni.