Mafia Island (Kisiwa cha Mafia) is an island and district in Tanzania’s Pwani Region. The island is the third largest in Tanzanian ocean territory, but it is not administratively part of the semi-autonomous region of Zanzibar, which has been politically independent since 1890. Mafia Island is the most populous island in Mafia District, one of six administrative districts of the Pwani coastline region. The island has a population of over 40,000 people. The economy is built around fishing, subsistence agriculture, and the Kilindoni market. Some tourists visit the island, primarily scuba divers, birdwatchers, game fisherman, and individuals seeking relaxation. Mangrove swamps, coastal forests, scrublands, and grasslands are the island’s primary ecosystems.