Babeldaob or Babelthuap, volcanic island, 143 sq mi (370 sq km), largest island of Palau, in the W Caroline Islands, W Pacific. In 2006, Palau's capital was moved from the island of Oreor (Koror) to Melekeok on the east coast of Babeldaob. Babeldaob, which has roughly 70% of the country's land area and is largely covered by forest, also has two freshwater lakes and Palau's highest peak, Mt. Ngerchelchuus (794 ft/242 m).