Mentawai Islands Regency

The Mentawai Islands have been administered as a regency within the West Sumatra (Sumatera Barat) province since 1999. The regency seat is Tua Pejat, on the island of Sipora. Padang, the capital of the province, lies on the Sumatran mainland opposite Siberut. The regency is divided into ten districts (kecamatan), tabulated below from south to north with their areas and their populations at the 2010 Census^[3] and the 2020 Census,^[4] together with the official estimates as of mid 2025.^[1] The table also includes the locations of the district administrative centres, the number of villages (all classed as rural desa) and the number of named offshore islands in each district, and its postcode.

Note: (a) Sikakap District covers the northern part of South Pagai Island and the southern part of North Pagai Island, plus some intervening small islands. Of its three desa, Matobek is entirely on North Pagai Island, while Sikakap and Taikato are mainly on North Pagai Island but each includes areas on South Pagai as well as the intervening small islands.

Inter-island ferries connect all the main islands, primarilly calling at the Pokhai wharf near Muara Sigep in the north of Siberut island, and at the Maileppet wharf in Muara Siberut (in the south of Siberut), at Tua Pejat and Siuban (on Sipora island), Pasar Puat and Sikakap (on North Pagai island), and Simakalo (on South Pagai island). All these ports are also connected by ferry services, including the Mentawai fast (operating every Tuesday, Thursday, and Saturday to Siberut) and ASDP vessels, which provide weekly services and occasional inter-island transit with the provincial capital of Padang.

Land connectivity on Siberut remain limited to specific routes. In the north of Siberut, a road connects the Pokhai wharf with Sikabaluan. In the south, a concrete road links Muntei, Muara Siberut, and the Maileppet wharf. Access to the interior villages, such as Madobag and Matotonan, is avalable via unpaved roads, though the west coast of Siberut is relatively poorly served by roads; inter-island services remain a vital transport alternative for most of the archipelago.

The islands have been separated from Sumatra since the mid-Pleistocene period, which has allowed at least twenty endemic species to develop amongst its flora and fauna. This includes six endemic primates: the Kloss's gibbon (Hylobates klossii), Mentawai macaque (Macaca pagensis), Siberut macaque (Macaca siberu), Mentawai langur (Presbytis potenziani), Siberut langur (Presbytis siberu), and pig-tailed langur (Simias concolor). They are highly endangered due to logging, unsustainable hunting, and conversion of rainforest to palm oil plantations.^[35] Some areas of the Mentawai Islands rainforest ecoregion are protected, such as the Siberut National Park. Red junglefowl, the Asian palm civet, and crab-eating macaque are also native.^[36]

The Mentawai Islands lie above the Sunda megathrust, a seismically active zone responsible for many great earthquakes. This megathrust runs along the southwestern side of Sumatra island, forming the interface between the Eurasian Plate and the Indo-Australian Plate.

Earthquake and tsunami activity has been high since the 2004 Indian Ocean earthquake. In 1833, the region was hit with an earthquake, possibly similar in size to the 2004 Indian Ocean earthquake;^[37] another large earthquake struck in 1797. On October 25, 2010, an earthquake in southern Sumatra led to a deadly tsunami that devastated villages in South and North Pagai.^[38] On March 3, 2016, an earthquake of 7.8 magnitudes occurred off the Indian Ocean, a few hundred kilometres from Mentawai islands, as a result of strike-slip faulting within the oceanic lithosphere of the Indo-Australia plate.^[39]

• Mentawai ethnic group
• Mentawai Festival