Mafia Island (“Chole Shamba”) is part of the Tanzanian Spice Islands, which consists also of Zanzibar and Pemba. Mafia is part of the Pwani Region and is governed from the mainland (not Zanzibar). Mafia has never been part of Zanzibar.
Mafia Island is also one of the 6 districts of the Pwani Region. According to the 2002 Tanzania National Census, the population of the Mafia District was 40,801. 
The people of Mafia Island are mainly fishermen; they combine their fishing activities with small scale cultivation of foods.
The island is a good retreat for adventure scuba divers, game fishermen and those seeking simple relaxation.
The Mafia island cluster consists of one large island (394km²) and many off-shore islands around it — inhabited as well as uninhabited, including Chole Island (2km²) with a population of 800. Chole Bay, Mafia’s protected deep-water anchorage and the original harbour, is studded with islands, sandbanks and beaches. The main town is Kilindoni. The stretch of water between the deltas of the xRufiji River and the island is called Mafia Channel.
The Mafia District is administratively divided into 7 wards: Baleni, Jibondo, Kanga, Kilindoni, Kirongwe, Kiegani, Mibulani.