Geography
Area: 245,860 sq. km. (95,000 sq. mi.), about the size of Oregon.
Cities: Capital--Conakry. Other cities--Guéckédou, Boké, Kindia, N'Zérékoré, Macenta, Mamou, Kankan, Faranah, Siguiri, Dalaba, Labe, Pita, Kamsar.
Terrain: Generally flat along the coast and mountainous in the interior.
The country's four geographic regions include a narrow coastal belt; pastoral highlands (the source of West Africa's major rivers); the northern savanna; and the southeastern rain forest.
Climate: Tropical.

Geography of Guinea
Guinea is located on the Atlantic Coast of West Africa and is bordered by Guinea-Bissau, Senegal, Mali, Côte d'Ivoire, Liberia, and Sierra Leone. The country is divided into four geographic regions: A narrow coastal belt (Lower Guinea); the pastoral Fouta Djallon highlands (Middle Guinea); the northern savannah (Upper Guinea); and a southeastern rain-forest region (Forest Guinea). The Niger, Gambia, and Senegal Rivers are among the 22 West African rivers that have their origins in Guinea.

The coastal region of Guinea and most of the inland have a tropical climate, with a rainy season lasting from April to November, relatively high and uniform temperatures, and high humidity. Conakry's year-round average high is 29oC (85oF), and the low is 23oC (74oF); its average annual rainfall is 430 centimeters (169 inches). Sahelian Upper Guinea has a shorter rainy season and greater daily temperature variations.
source: http://www.state.gov