The following outline is provided as an overview of and topical guide to Tonga: Tonga is a sovereign island nation located in the South Pacific Ocean. Tonga comprises the Tonga Archipelago of 169 islands, 36 of them inhabited, stretching over a distance of about 800 kilometres (500 mi) in a north-south line. The islands lie south of Samoa and are about one-third of the way from New Zealand to Hawaii. Tonga is the only surviving monarchy among the island nations of the Pacific Ocean, as well as being the only island nation never to have been formally colonized.