The Guinean Forests of West Africa hotspot encompasses all of the lowland forests of political West Africa, stretching from Guinea and Sierra Leone eastward to the Sanaga River in Cameroon. This includes the countries of Liberia, Côte d'Ivoire, Ghana, Togo, Benin, and Nigeria, which maintain remnant fragments of the forests. The hotspot also includes four islands in the Gulf of Guinea: Bioko and Annobon, which are both part of Equatorial Guinea, and São Tomé and Príncipe, which together form an independent nation. Bioko is a continental-shelf island, whereas the remaining three are oceanic.
The hotspot includes two distinct sub-regions, which incorporate several important forest refugia created by the retraction and fragmentation of forests during the Pleistocene Epoch. The first sub-region, Upper Guinea, stretches from southern Guinea into eastern Sierra Leone and through Liberia, Côte d'Ivoire and Ghana into western Togo. The second sub-region, Nigeria-Cameroon, extends along the coast from western Nigeria to the Sanaga River in southwestern Cameroon. The two sub-regions are separated by the Dahomeny Gap in Benin, an area of farmland, savanna and highly degraded dry forest. The hotspot supports several important montane regions, including the Cameroon Highlands (Mt. Cameroon, at 4,095 meters, is the highest peak in West Africa) and the Nimba Highlands.
The Guinean forests consist of a range of distinct vegetation zones varying from moist forests along the coast, freshwater swamp forests (for example, around the Niger Delta), semi-deciduous forests inland with prolonged dry seasons. Of all West African countries, only Liberia lies entirely within the moist forest zone, although a substantial portion of Sierra Leone also falls within the boundaries.