Babeldaob (also Babelthuap) is the largest island in the island nation of the Republic of Palau. It is in the western Caroline Islands, and the second largest island (after Guam) in the Micronesia region of Oceania. Palau's capital, Ngerulmud, is located on Babeldaob, in Melekeok State.
Babeldaob is one of the most underdeveloped populated islands in the Pacific Ocean. The area of Babeldaob, , makes up over 70% of the land area of the entire Republic of Palau. It has about 30% of the country's population, with about 6,000 people living on it.
Babeldaob is located northeast of Koror Island, and its northern portion contains the site of the new national capital, Ngerulmud. The southern end of the island is in Airai State, Palau's second-most populous state. The Airai Airport on the island is the nation's principal airport.
The Koror-Babeldaob Bridge links Babeldaob Island at Airai to Koror Island.
Unlike most of the islands of Palau, Babeldaob is mountainous. It contains Palau's highest point, the -tall Mount Ngerchelchuus. Babeldaob's eastern coast has many sandy beaches, in particular north from Melekeok to Ngaraard, and the island's western coast has a shoreline with many mangrove forests.
Of the 16 states of Palau, Babeldaob encompasses 10, which are:
Aimeliik
Airai
Melekeok
Ngaraard
Ngarchelong
Ngardmau
Ngatpang
Ngchesar
Ngeremlengui
Ngiwal
The central forested Middle Ridge of Babeldaob encompasses the headwaters of most of the island’s watersheds. Some 13,767 ha in area, it has been designated an Important Bird Area (IBA) by BirdLife International because it supports populations of most of Palau’s endemic birds, including Micronesian megapodes, Palau ground doves, Micronesian imperial pigeons, Palau fruit doves, swiftlets, owls and kingfishers, Micronesian myzomelas, morningbirds, Palau fantails, flycatchers and bush warblers, dusky and citrine white-eyes, and Micronesian starlings. The Western Ridge IBA adjoins Middle Ridge in the north-west of the island.