Riau in the context of Central Sumatra

The Riau Islands (Indonesian: Kepulauan Riau; Jawi: كڤولاوان رياو) is a province of Indonesia consisting of a group of islands located in the western part of the country. It was established in 2002 after being separated from the neighboring Riau Province. The capital of the province is Tanjung Pinang, while the largest city is Batam. It shares a maritime border with Riau and Jambi to the west, Bangka Belitung Islands to the south, Singapore to the northeast, Malaysia and West Kalimantan to the east, and Vietnam and Cambodia to the north. It comprises a total of 2,408 islands (1,798 having names) scattered between Sumatra, Malay Peninsula, and Borneo including the Riau Archipelago. Situated on one of the world's busiest shipping lanes along the Malacca Strait and the Natuna Sea (South China Sea), the province shares water borders with neighboring countries such as Singapore, Malaysia, and Brunei. The Riau Islands also have relatively large potential mineral resources and energy, as well as marine resources.

The Riau Islands have played a significant role in the maritime history and civilization of the Nusantara region. Between the 7th and 13th centuries, the area was influenced by the powerful Srivijaya Empire, a major maritime kingdom that controlled trade routes along the Malacca Strait. Evidence of Srivijaya's influence in the Riau Islands can be seen from the discovery of the Pasir Panjang Inscription [id] in Karimun Regency, which shows the existence of religious practices through Buddha's footprints, indicating early settlement and the spread of Buddhism long before the arrival of Islam.

Sumatra (/sʊˈmɑːtrə/) is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the sixth-largest island in the world at 482,286.55 km (182,812 mi.), including adjacent islands such as the Simeulue, Nias, Mentawai, Enggano, Riau Islands, Bangka Belitung and Krakatoa archipelago.

Sumatra is an elongated landmass spanning a diagonal northwest–southeast axis. The Indian Ocean borders the northwest, west, and southwest coasts of Sumatra, with the island chain of Simeulue, Nias, Mentawai, and Enggano off the western coast. In the northeast, the narrow Strait of Malacca separates the island from the Malay Peninsula, which is an extension of the Eurasian continent. In the southeast, the narrow Sunda Strait, containing the Krakatoa archipelago, separates Sumatra from Java. The northern tip of Sumatra is near the Andaman Islands, while off the southeastern coast lie the islands of Bangka and Belitung, Karimata Strait and the Java Sea. The Bukit Barisan mountains, which contain several active volcanoes, form the backbone of the island, while the northeastern area contains large plains and lowlands with swamps, mangrove forest and complex river systems. The equator crosses the island at its centre in West Sumatra and Riau provinces. The climate of the island is tropical, hot, and humid. Lush tropical rain forest once dominated the landscape.

The Riau Archipelago is a geographic term (as opposed to administrative region) for the core group of islands within the Riau Islands Province in Indonesia, and located south of Singapore and east of Riau on Sumatra. Before the province of Riau Islands was formed, there was no ambiguity in term; however, in Indonesian language, both the archipelago and administrative province are referred to simply as "Kepulauan Riau". The province may have the word "Provinsi" preceding it for clarity. Additionally, the term BBK for Batam Bintan Karimun may refer to the archipelago.

Jambi is a province of Indonesia. It is located on the east coast of central Sumatra and stretches to the Barisan Mountains in the west. Its capital and largest city is also called Jambi. It is bordered by the provinces of Riau to the north, West Sumatra to the west, Bengkulu to the southwest, South Sumatra to the south, and shares a maritime border with the Riau Islands to the east and the Pacific Ocean to the east. The province has a land area of 49,026.58 km, and a sea area of 3,274.95 km. Its area is comparable to the European country of Slovakia or Smolensk Oblast. It had a population of 3,092,265 according to the 2010 census and 3,548,228 according to the 2020 census; the official estimate of population as of mid-2024 was 3,745,746 (comprising 1,893,490 males and 1,830,790 females).

North Sumatra (Indonesian: Sumatera Utara; Batak: ᯘᯮᯔᯖᯩᯒ ᯥᯖᯒ) is a province of Indonesia located in the northern part of the island of Sumatra. Its capital and largest city is Medan on the east coast of the island. It borders Aceh to the northwest, Riau to the southeast, West Sumatra to the south, the Indian Ocean to the west, and the Strait of Malacca (with a maritime border with Malaysia) to the east.

With a 2020 population around 14.8 million and a mid-2024 estimate around 15.6 million, North Sumatra is Indonesia's fourth most populous province and the most populous province outside of Java Island. At 72,460.74 square kilometres (27,977.25 sq mi), North Sumatra is the third-largest province in area on the island of Sumatra behind South Sumatra and Riau. Major ethnic groups include the Malay, native to the east coast; several Batak groups, indigenous to the west coast and central highlands; the Nias people of Nias Island and its surrounding islets; and Chinese, Javanese, and Indian peoples, who first migrated to Sumatra during Dutch rule.

Pekanbaru ([pəkanˈbaru]) is the capital city of the Indonesian province of Riau, and a major economic center on the eastern side of Sumatra Island with its name derived from the Malay (Indonesian) word for 'new market' ('pekan' is market and 'baru' is new).It has an area of 632.26 km (244.12 sq mi), with a population of 897,767 at the 2010 Census, and 983,356 at the 2020 Census; the official estimate as at mid 2024 was 1,167,599 (comprising 586,917 males and 580,682 females). It is located on the banks of the Siak River, which flows into the Strait of Malacca, Pekanbaru has direct access to the busy strait and has long been known as a trading port.

A settlement has existed on the site since the 17th century. In the late 19th century, the city was developed to serve the coffee and coal industries, and the Dutch built roads to help ship goods to Singapore and Malacca. This city has an airport called Sultan Syarif Kasim II International Airport, and a port called Sungai Duku that is located by the Siak River.

Minangkabau (/ˌmēnäŋkəˈbau̇/ MEE-nahng-kah-bow; Baso Minangkabau, Jawi: بهاس منڠكربو‎, IPA: [ˈbaso mi.naŋˈka.bau]), simply known as Minang, is an Austronesian language spoken by the Minangkabau of West Sumatra, the western part of Riau, the southern and western coast of Aceh, the northern part of Bengkulu and Jambi, also in several cities throughout Indonesia by migrated Minangkabau. The language is also a lingua franca along the western coastal region of the province of North Sumatra, and is even used in parts of Aceh, where it is known as the Aneuk Jamee dialect.

Minangkabau is similar to Malay. The relationship between the languages is characterized in different ways. Some see Minangkabau as an early variety of Malay, while others think of Minangkabau as a distinct (Malayic) language.

Banjarese (/ˈbændʒəˌriːz/ BAN-juh-reez; Basa Banjar, Jaku Banjar, Jawi script: باس بنجر‎ IPA: [basa bandʒar], [dʒaku bandʒar]) or simply Banjar, is an Austronesian language of the Malayic branch predominantly spoken by the Banjarese—an indigenous ethnic group native to Banjar regions— in the southeastern Kalimantan of Indonesia. The Banjarese language is the de facto lingua franca for various indigenous community especially in South Kalimantan, as well as Central Kalimantan (notably in Seruyan Regency and Sukamara Regency) and East Kalimantan in general.

Banjarese also has significant population in other provinces in Indonesia, especially in Sumatra (Riau and North Sumatra) even some regencies in Riau has a Banjarese majority population like in Indragiri Hilir Regency.

West Sumatra (Indonesian: Sumatera Barat) 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 km (16,262.45 sq mi), or about the same size as Switzerland or Penza Oblast, with a population of 5,534,472 at the 2020 census. The official estimate at mid 2024 was 5,836,160 (comprising 2,940,270 males and 2,895,880 females). 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.

West Sumatra is home to the Minangkabau people, although the traditional Minangkabau region is actually wider than the province's boundaries, covering up to the western coast of North Sumatra, the southwestern coast of Aceh, the western region of Riau, the western region of Jambi, the northern region of Bengkulu, and Negeri Sembilan in Malaysia. Another native ethnic group is the Mentawai people, who inhabit the western islands of the same name. Islam is a predominant religion in the province, with about 97.4% of the total population.

Malayisation (Commonwealth spelling) or Malayization (North American and Oxford spelling) is a process of assimilation and acculturation, that involves acquisition (Malay: Masuk Melayu, literally "embracing Malayness") or imposition (Malay: Pemelayuan or Melayuisasi) of elements of Malay culture, in particular, Islam and the Malay language, as experienced by non-Malay populations of territories fully controlled or partially influenced by historical Malay sultanates and modern Malay-speaking countries. It is often described as a process of civilisational expansion, drawing a wide range of indigenous peoples into the Muslim, Malay-speaking polities of Maritime Southeast Asia. Examples of Malayisation have occurred throughout Asia including in Brunei, Cambodia, Indonesia, Malaysia, Singapore, and Sri Lanka.

Malayisation started to occur during the territorial and commercial expansion of Melaka Sultanate in the 15th century, which spread the language, culture, and Islam to the Maritime Southeast Asia. Following the demise of Melaka in the early 16th century, instances of this assimilation of people from different ethnic origins into Malay culture, continued under numerous sultanates that emerged in Malay Peninsula, Sumatra, Riau Islands and Borneo. Malayisation could either be voluntary or forced and is most visible in the case of territories where the Malay language or culture were dominant or where their adoption could result in increased prestige or social status.

Buddhism has a long history in Indonesia, and it is one of the six recognized religions in the country, along with Islam, Christianity (Protestantism and Catholicism), Hinduism and Confucianism. According to 2023 estimates roughly 0.71% of the total citizens of Indonesia were Buddhists, numbering around 2 million. Most Buddhists are concentrated in Jakarta, Riau, Riau Islands, Bangka Belitung, North Sumatra, and West Kalimantan. These totals, however, are probably inflated, as practitioners of Taoism, Tridharma, Yiguandao, and other Chinese folk religions, which are not considered official religions of Indonesia, likely declared themselves as Buddhists on the most recent census. Today, the majority of Buddhists in Indonesia are Chinese Indonesians, but communities of native Buddhists (such as Javanese, Tenggerese, Sasak, Balinese, Dayak, Alifuru, Batak, and Karo) also exist.

The Riau Islands (Indonesian: Kepulauan Riau; Jawi: كڤولاوان رياو) is a province of Indonesia consisting of a group of islands located in the western part of the country. It was established in 2002 after being separated from the neighboring Riau Province. The capital of the province is Tanjung Pinang, while the largest city is Batam. It shares a maritime border with Riau and Jambi to the west, Bangka Belitung Islands to the south, Singapore to the northeast, Malaysia and West Kalimantan to the east, and Vietnam and Cambodia to the north. It comprises a total of 2,408 islands (1,798 having names) scattered between Sumatra, Malay Peninsula, and Borneo including the Riau Archipelago. Situated on one of the world's busiest shipping lanes along the Malacca Strait and the Natuna Sea (South China Sea), the province shares water borders with neighboring countries such as Singapore, Malaysia, and Brunei. The Riau Islands also have relatively large potential mineral resources and energy, as well as marine resources.

The Riau Islands have played a significant role in the maritime history and civilization of the Nusantara region. Between the 7th and 13th centuries, the area was influenced by the powerful Srivijaya Empire, a major maritime kingdom that controlled trade routes along the Malacca Strait. Evidence of Srivijaya's influence in the Riau Islands can be seen from the discovery of the Pasir Panjang Inscription (id) in Karimun Regency, which shows the existence of religious practices through Buddha's footprints, indicating early settlement and the spread of Buddhism long before the arrival of Islam.

Muara Takus (Indonesian: Candi Muara Takus) is a Buddhist temple complex, thought to belong to the Srivijaya empire. It is situated in Kampar Regency in Riau province, Sumatra, Indonesia. Its surviving temples and other archaeological remains are thought to date to the 11th and 12th century AD. It is one of the largest and best-preserved ancient temple complexes in Sumatra.

Kampar is a regency (kabupaten) of Riau Province of Indonesia. The regency formerly included a much larger part of Riau Province, but on 4 October 1999 the western districts were split off to form a separate Rokan Hulu Regency, and the eastern districts were split off to form a new Pelalawan Regency. It now has an area of 11,289.28 km (about 40% of its former area) and had a population of 688,204 at the 2010 Census, and 841,332 at the 2020 Census; the official estimate as at mid 2024 was 898,973 (comprising 459,172 males and 439,801 females). The administrative centre of the regency is located at the town of Bangkinang.

The Lingga Regency (Indonesian: Kabupaten Lingga) is a group of 600 islands in Indonesia, located south of Singapore and along both sides of the equator, off the eastern coast of Riau Province on Sumatra island. They are due south of the populated Riau Archipelago, known for the industrial island of Batam and the tourist-frequented island of Bintan, although the Lingga Islands themselves are rarely visited due to the infrequent local transportation. The equator goes through the northern tip of Lingga Island, the main island in the archipelago.

Administratively they form a Regency of the Riau Islands Province with a land area of 2,250.45 km and a population of 86,244 people at the 2010 census and 98,633 at the 2020 census; the official estimate as at mid 2023 was 102,474. The regency seat lies at Daik on Lingga Island.

Riau Malays (Malay: Orang Melayu Riau, Jawi: ملايو رياو‎) are a sub-group of Malays native to the provinces of Riau and the Riau Islands of eastern Sumatra, Indonesia. They only make up 29% of the population of the Riau Islands, and around 45% of the population of Riau. Riau Malays, especially in the coastal areas of Riau and the Riau Islands, share the same cultural, historical and linguistic backgrounds with Johorean and Singaporean Malays due to their common Malaccan origin in the 15th century.

The Siak is a river of Riau province, in the east of Sumatra, Indonesia, about 1000 km northwest of the capital Jakarta. Approximately 370 kilometres in length, the Siak is a blackwater river which owes its brown color to dissolved organic matter (DOM) leached from surrounding, heavily disturbed peat soils; it is heavily polluted, notably by the petroleum industry. It flows through the town of Pekanbaru before emptying into the Strait of Malacca.