From the Wikipedia page 
Mafia Island ("Chole Shamba") is an island in Tanzania. As one of the six districts of the Pwani Region, Mafia Island is governed from the mainland, not from the semi-autonomous region of Zanzibar, of which it has never been considered to be a part politically.
The Mafia District is administratively divided into seven wards, listed with area and population:<
|Baleni||132.1||9,137||Baleni, Kungwi, Ndagoni, Chunguruma|
|Jibondo||21.9||3,405||Jibondo, Chole, Juani|
|Kirongwe||77.0||5,260||Kirongwe, Jimbo, Banja, Jojo|
|Mibulani||52.3||4,363||Miburani, Mlongo, Chemchem|
|Mafia Island||413||40,801||20 villages|