Tonga is an archipelagic nation comprising some 150 islands, of which about 35 are inhabited, as well as many smaller islets and reefs. The islands, whose collective land area is close to 700 km2, are distributed in three main groups - Tongatapu (location of the capital and administrative centre, Nuku’alofa) and neighbouring islands in the south, the Ha’apai group located centrally, and the Vava’u group to the north. Other islands extend the archipelago further north and south beyond the main groups.