Mangareva is the central and largest island of the Gambier Islands in French Polynesia. It is surrounded by smaller islands: Taravai in the southwest, Aukena and Akamaru in the southeast, and islands in the north. Mangareva has a permanent population of 1,641 (2007) and the largest village on the island, Rikitea, is the chief town of the Gambier Islands.
The island is approximately 8 km (5.0 mi) long and, at 18 km² (7 mi²), it comprises about 56% of the land area of the whole Gambier group. Mangareva has a high central ridge which runs the length of the island. The highest point in the Gambiers is Mt. Duff, on Mangareva, rising to 441 m along the island's south coast. The island has a large lagoon 15 miles in diameter containing reefs whose fish and shellfish helped ancient islanders survive much more successfully than on nearby islands with no reefs.
The Gambier Islands or Mangareva Islands (French: Îles Gambier or Archipel des Gambier) are a small group of islands in French Polynesia, located at the southeast terminus of the Tuamotu archipelago. They are generally considered a separate island group from Tuamotu both because their culture and language (Mangarevan) are much more closely related to those of the Marquesas Islands, and because, while the Tuamotus comprise several chains of coralatolls, the Gambiers are of volcanic origin. Because of their proximity, the Acteon Group, and the nearby atoll of Temoe (23°20′46″S134°28′28″W / 23.34611°S 134.47444°W / -23.34611; -134.47444) are sometimes included among the Gambiers.