Coordinates: 20°S 175°W / 20°S 175°W / -20; -175. Tonga (/ˈtɒŋə/ or /ˈtɒŋɡə/; Tongan: [ˈtoŋa] Puleʻanga Fakatuʻi ʻo Tonga), officially the Kingdom of Tonga, is a Polynesian sovereign state and archipelago comprising 169 islands of which 36 are inhabited.