The U.N. defines West Africa as having 18 countries .
West Africa has been defined as including 18 countries : Benin , Burkina Faso , the island nation of Cape Verde , Gambia , Ghana , Guinea , Guinea-Bissau , Ivory Coast , Liberia , Mali , Mauritania , Niger , Nigeria , the island of Saint Helena , Senegal , Sierra Leone , São Tomé and Príncipe and Togo .
West Africa