Oreor (ôr´āôr´) or Koror (kôr´rô´), volcanic island (c.3 sq mi/7.8 sq km; 1990 pop. 10,501), Palau, in the W Caroline Islands, W Pacific. Most of the republic's population lives there, and the island was the site of the capital from independence, in 1994, to 2006, when Melekeok became the capital. The island remains Palau's economic hub, and the country's main airport is there. A highway connects Oreor to the main harbor on Malakal Island. Oreor also was formerly known Corrora.