# Mentawai Islands Regency

The Mentawai Islands Regency is a regency of West Sumatra Province which consists of a chain of about a hundred islands and islets approximately 150 km (93 mi) off the western coast of Sumatra in Indonesia. They cover a land area of 6,034 km$^2$ (2,330 sq mi) and had a population of 76,173 at the 2010 Census and 87,623 at the 2020 Census; the official estimate as of mid-2023 was 95,068.
Siberut at 3,878 km$^2$ (1,497 sq mi) is the largest of the islands, occupying 64.27% of the land area of the regency. The other major islands are Sipura (or Sipora), North Pagai (Pagai Utara), and South Pagai (Pagai Selatan). The islands lie off the Sumatran coast, across the Mentawai Strait. The indigenous inhabitants of the islands are known as the Mentawai people. The Mentawai Islands have become a noted destination for surfing, with over 40 boats offering surf charters to international guests.

## Administrative districts

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 and the 2020 Census, together with the official estimates as at mid-2023. 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.
| Name of District (kecamatan) | English Name | Area in km$^2$ | Pop'n 2010 Census | Pop'n 2020 Census | Pop'n mid 2023 Estimate | Admin centre | No. of villages | No. of islands | Post code |
| Pagai Selatan | South Pagai | 851.28 | 8,782 | 9,373 | 10,279 | Bulasat | 4 | 31 | 25391 |
| Sikakap $^{(a)}$ | Central Pagai | 312.60 | 9,531 | 10,219 | 10,821 | Taikako | 3 | 8 | 25399 |
| Pagai Utara | North Pagai | 371.25 | 5,212 | 6,031 | 6,495 | Saumanganya | 3 | 9 | 25390 |
| Sipora Selatan | South Sipora | 348.33 | 8,460 | 9,812 | 10,552 | Sioban | 7 | 3 | 25392 |
| Sipora Utara | North Sipora | 272.40 | 9,097 | 11,968 | 13,405 | Sido Makmur | 6 | 12 | 25398 |
| Siberut Selatan | South Siberut | 328.00 | 8,446 | 9,933 | 10,711 | Muara Siberut | 5 | 1 | 25397 |
| Siberut Barat Daya | Southwest Siberut | 1,013.83 | 6,069 | 7,058 | 7,686 | Pasakiat Taileleu | 3 | 17 | 25393 |
| Siberut Tengah | Central Siberut | 589.75 | 6,069 | 7,089 | 7,716 | Saibi Samukop | 3 | 5 | 25396 |
| Siberut Utara | North Siberut | 782.68 | 7,774 | 8,337 | 9,151 | Muara Sikabaluan | 6 | 4 | 25395 |
| Siberut Barat | West Siberut | 1,163.64 | 6,733 | 7,803 | 8,252 | Simalegi | 3 | 1 | 25394 |
| Totals | | 6,033.76 | 76,173 | 87,623 | 96,068 | Tuapejat | 43 | 111 | |
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 the 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.

### Villages

The ten districts comprise forty-three rural villages (desa) listed below with their areas and their populations as officially estimated for mid 2023:
| Kode Wilayah | Name of desa | Area in km$^2$ | Pop'n Estimate mid 2023 |
| 13.09.10.2001 | Sinaka (Sinakak) | 265.87 | 2,455 |
| 13.09.10.2002 | Bulasat | 224.00 | 2,703 |
| 13.09.10.2003 | Malakopa (Malakopak) | 127.63 | 2,745 |
| 13.09.10.2004 | Makalo | 233.78 | 2,376 |
| 13.09.10 | Totals Pagai Selatan District | 851.28 | 10,279 |
| 13.09.09.2001 | Sikakap | 35.82 | 5,226 |
| 13.09.09.2002 | Taikako | 168.20 | 3,510 |
| 13.09.09.2003 | Matobe (Matobek) | 108.59 | 2,085 |
| 13.09.09 | Totals Sikakap District | 312.60 | 10,821 |
| 13.09.01.2007 | Betumonga | 76.91 | 1,303 |
| 13.09.01.2008 | Silabu | 97.63 | 1,308 |
| 13.09.01.2009 | Saumanganya | 196.72 | 3,884 |
| 13.09.01 | Totals Pagai Utara District | 371.25 | 6,495 |
| 13.09.02.2001 | Bosua | 40.78 | 1,780 |
| 13.09.02.2002 | Beriulou | 78.93 | 1,081 |
| 13.09.02.2003 | Nemnemleleu | 46.91 | 1,377 |
| 13.09.02.2004 | Mara | 62.27 | 1,198 |
| 13.09.02.2006 | Sioban | 16.75 | 2,329 |
| 13.09.02.2007 | Matobe | 23.62 | 1,265 |
| 13.09.02.2008 | Saureinu | 79.47 | 1,522 |
| 13.09.02 | Totals Sipora Selatan District | 348.33 | 10,552 |
| 13.09.08.2001 | Betumonga | 110.58 | 1,339 |
| 13.09.08.2002 | Goisooinan | 56.07 | 1,226 |
| 13.09.08.2003 | Tuapejat | 86.52 | 6,404 |
| 13.09.08.2004 | Sido Makmur | 6.07 | 985 |
| 13.09.08.2005 | Bukit Pamewa | 7.72 | 850 |
| 13.09.08.2006 | Sipora Jaya | 5.44 | 2,601 |
| 13.09.08 | Totals Sipora Utara District | 272.40 | 13,405 |
| 13.09.03.2002 | Muara Siberut | 17.75 | 3,259 |
| 13.09.03.2003 | Maileppet | 18.77 | 1,833 |
| 13.09.03.2004 | Muntei | 90.94 | 1,798 |
| 13.09.03.2005 | Matotonan | 85.65 | 1,336 |
| 13.09.03.2007 | Madobag | 114.89 | 2,485 |
| 13.09.03 | Totals Siberut Selatan District | 328.00 | 10,711 |
| 13.09.06.2001 | Katurei | 128.35 | 2,406 |
| 13.09.06.2002 | Sagulubbeg | 469.47 | 1,676 |
| 13.09.06.2003 | Pasakiat Taileleu | 416.00 | 3,604 |
| 13.09.06 | Totals Siberut Barat Daya District | 1,013.83 | 7,686 |
| 13.09.07.2001 | Saibi Samukop | 230.63 | 3,692 |
| 13.09.07.2002 | Cimpungan | 93.84 | 1,223 |
| 13.09.07.2003 | Saliguma | 265.28 | 2,801 |
| 13.09.07 | Totals Siberut Tengah District | 589.75 | 7,716 |
| 13.09.04.2003 | Bojakan | 263.04 | 1,168 |
| 13.09.04.2004 | Sotboyak | 42.83 | 719 |
| 13.09.04.2005 | Mongan Poula | 30.61 | 1,085 |
| 13.09.04.2006 | Muara Sikabaluan | 43.41 | 2,638 |
| 13.09.04.2007 | Sirilogui | 107.24 | 1,369 |
| 13.09.04.2008 | Malancan | 295.55 | 2,172 |
| 13.09.04 | Totals Siberut Utara District | 782.68 | 9,151 |
| 13.09.05.2001 | Simatalu Sipokak | 309.47 | 3,642 |
| 13.09.05.2002 | Simalegi | 559.19 | 2,396 |
| 13.09.05.2003 | Sigapokna | 294.98 | 2,214 |
| 13.09.05 | Totals Siberut Barat District | 1,163.64 | 8,252 |

## Tourism
### Surfing

Macaronis was first discovered in 1980 by pioneer surf discoverers Chris Goodnow, Scott Wakefield, and Tony Fitzpatrick, who originally named the break ‘P-Land’ on their first visit (after Pasangan Bay / Pagai Islands). Amazingly, and considering the remote location, P-Land may have been the first wave surfed in the Mentawai Islands. Lances Right was discovered a full 10 years later, while Chris, Scott, and Tony continued to keep their discovery a secret. They returned in 1981 with friend Tim Annand, and again on a boat trip in the 90’s.
The first photos of the surf breaks in the Mentawais area were leaked after a surf trip in 1992 aboard the MV Indies Trader, with professional surfers Ross Clarke-Jones, Tom Carroll, and Martin Potter. Ever since then, the Mentawai Islands have been well on the radar of surf travellers around the world. At the West of Sumatra, the Mentawai Islands have the most consistent surf breaks in Indonesia making it one of the preferred choices for serious surfers. The tropical waters surrounding the islands offer year-round waves up to 15 ft (4.6 m).

## Ecology

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. 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.

## Seismic activity

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; 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. 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.