Guadeloupe is a group of islands that is an overseas department of France. Located in the French West Indies, off the north-western coast of South America, in the eastern Caribbean Sea. The two principal islands, separated by the Salée River, a narrow arm of the Caribbean Sea, are Basse-Terre on the west and Grande-Terre on the east. Nearby island dependencies are Marie-Galante, La Désirade, and Les Saintes; the other dependencies, Saint-Barthélemy and Saint Martin, are located about 250 km (about 155 mi) to the northwest. Basse-Terre is the most mountainous of the islands and contains the highest point, Soufrière (1484 m/4869 ft), an active volcano. The total area of Guadeloupe is 1780 sq km (687 sq mi).