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 kilometres off the western coast of Sumatra in Indonesia. They cover a land area of 6,033.76 km2 and had a population of 76,173 at the 2010 Census and 87,623 at the 2020 Census; the official estimate as of mid-2022 was 89,401 - comprising 46,431 males and 42,970 females. Siberut at 3,838.25 square kilometres is the largest of the islands. The other major islands are Sipura, North Pagai, and South Pagai. 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.

West Sumatra is a province of Indonesia. It is on the west coast of the island of Sumatra and includes the Mentawai Islands off that coast. West Sumatra borders the Indian Ocean to the west, as well as the provinces of North Sumatra to the north, Riau to the northeast, Jambi to the southeast, and Bengkulu to the south. The province has an area of 42,119.54 km2 (16,262.45 sq mi),or about the same size as Switzerland,with a population of 5,534,472 at the 2020 census. The official estimate at mid 2022 was 5,640,629. The province is subdivided into twelve regencies and seven cities. It has relatively more cities than other provinces outside Java, although several of them are relatively low in population compared with cities elsewhere in Indonesia. Padang is the province's capital and largest city.