Unguja (also referred to as Zanzibar Island or simply Zanzibar, in Ancient Greek Menuthias, Μενουθιάς - as mentioned in The Periplus of the Erythraean Sea, in Greek: Περίπλους τὴς Ἐρυθράς Θαλάσσης -) is the largest and most populated island of Zanzibar, in Tanzania.
Unguja is a hilly island, about 85 km long (north-south) and 30 km wide (east-west) at its widest, with an overall area of about 1666 km². It is located in the southern half of the Zanzibar Archipelago, in the Indian Ocean, about 59 km south of the second largest island of the archipelago, Pemba. Unguja and mainland Tanzania are separated by the Zanzibar Channel.
Unguja is surrounded by a number of smaller islands and islets, with only two of them, Tumbatu and Uzi, being inhabited. Other minor islands around Unguja include Bawe, Chapwani, Changuu, Chumbe, Kizingo, Kwale, Latham, Mautani, Miwi, Mnemba, Mwana wa Mwana, Nianembe, Popo, Pungume, and Ukanga.