Sumatra () is one of the
Sunda Islands
The Sunda Islands (; Tetun: ''Illa Sunda'') are a group of islands in the Indonesian Archipelago. They consist of the Greater Sunda Islands and the Lesser Sunda Islands.
Etymology
"Sunda" denotes the continental shelves or landmasses: the Sun ...
of western
Indonesia
Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...
. 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
2 (182,812 mi.
2), including adjacent islands such as the
Simeulue,
Nias
Nias (, Nias: ''Tanö Niha'') is an island located off the western coast of Sumatra, Indonesia. Nias is also the name of the archipelago () of which the island is the centre, but also includes the Batu Islands to the southeast and the small ...
,
Mentawai,
Enggano,
Riau Islands
The Riau Islands () is a provinces of Indonesia, 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 capit ...
,
Bangka Belitung and
Krakatoa archipelago.
Sumatra is an elongated landmass spanning a diagonal northwest–southeast axis. The
Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...
borders the northwest, west, and southwest coasts of Sumatra, with the island chain of
Simeulue,
Nias
Nias (, Nias: ''Tanö Niha'') is an island located off the western coast of Sumatra, Indonesia. Nias is also the name of the archipelago () of which the island is the centre, but also includes the Batu Islands to the southeast and the small ...
,
Mentawai, and
Enggano off the western coast. In the northeast, the narrow
Strait of Malacca
The Strait of Malacca is a narrow stretch of water, long and from wide, between the Malay Peninsula to the northeast and the Indonesian island of Sumatra to the southwest, connecting the Andaman Sea (Indian Ocean) and the South China Sea (Pa ...
separates the island from the
Malay Peninsula
The Malay Peninsula is located in Mainland Southeast Asia. The landmass runs approximately north–south, and at its terminus, it is the southernmost point of the Asian continental mainland. The area contains Peninsular Malaysia, Southern Tha ...
, which is an extension of the
Eurasia
Eurasia ( , ) is a continental area on Earth, comprising all of Europe and Asia. According to some geographers, Physical geography, physiographically, Eurasia is a single supercontinent. The concept of Europe and Asia as distinct continents d ...
n continent. In the southeast, the narrow
Sunda Strait
The Sunda Strait () is the strait between the Indonesian islands of Java island, Java and Sumatra. It connects the Java Sea with the Indian Ocean.
Etymology
The strait takes its name from the Sunda Kingdom, which ruled the western portion of Ja ...
, containing the Krakatoa archipelago, separates Sumatra from
Java
Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...
. The northern tip of Sumatra is near the
Andaman Islands
The Andaman Islands () are an archipelago, made up of 200 islands, in the northeastern Indian Ocean about southwest off the coasts of Myanmar's Ayeyarwady Region. Together with the Nicobar Islands to their south, the Andamans serve as a mari ...
, while off the southeastern coast lie the islands of Bangka and Belitung,
Karimata Strait and the
Java Sea
The Java Sea (, ) is an extensive shallow sea on the Sunda Shelf, between the Indonesian islands of Borneo to the north, Java to the south, Sumatra to the west, and Sulawesi to the east. Karimata Strait to its northwest links it to the South Ch ...
. 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
Mangrove forests, also called mangrove swamps, mangrove thickets or mangals, are productive wetlands that occur in coastal intertidal zones. Mangrove forests grow mainly at tropical and subtropical latitudes because mangrove trees cannot withsta ...
and complex river systems. The
equator
The equator is the circle of latitude that divides Earth into the Northern Hemisphere, Northern and Southern Hemisphere, Southern Hemispheres of Earth, hemispheres. It is an imaginary line located at 0 degrees latitude, about in circumferen ...
crosses the island at its centre in
West Sumatra
West Sumatra () is a Provinces of Indonesia, 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 ...
and
Riau
Riau (Jawi script, Jawi: ) is a Provinces of Indonesia, province of Indonesia. It is located on the central eastern coast of the island of Sumatra, and extends from the eastern slopes of the Barisan Mountains to the Malacca Strait, including s ...
provinces. The climate of the island is
tropical
The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...
, hot, and humid. Lush
tropical rain forest once dominated the landscape.
Sumatra has a wide range of plant and animal species but has lost almost 50% of its tropical rainforest in the last 35 years. Many species are now
critically endangered
An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...
, such as the
Sumatran ground cuckoo, the
Sumatran tiger
The Sumatran tiger is a population of ''Panthera tigris sondaica'' on the Indonesian island of Sumatra. It is the only surviving tiger population in the Sunda Islands, where the Bali tiger, Bali and Javan tigers are extinct.
DNA sequencing, Sequ ...
, the
Sumatran elephant, the
Sumatran rhinoceros
The Sumatran rhinoceros (''Dicerorhinus sumatrensis''), also known as the Sumatran rhino, hairy rhinoceros or Asian two-horned rhinoceros, is a rare member of the family Rhinocerotidae and one of five extant species of rhinoceros; it is the o ...
, and the
Sumatran orangutan
The Sumatran orangutan (''Pongo abelii'') is one of the three species of orangutans. Critically endangered, and found only in the north of the Indonesian island of Sumatra, it is rarer than the Bornean orangutan but more common than the recently ...
.
Deforestation
Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. Ab ...
on the island has also resulted in serious seasonal smoke haze over neighbouring countries, such as the
2013 Southeast Asian haze which caused considerable tensions between Indonesia and affected countries
Malaysia
Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...
and
Singapore
Singapore, officially the Republic of Singapore, is an island country and city-state in Southeast Asia. The country's territory comprises one main island, 63 satellite islands and islets, and one outlying islet. It is about one degree ...
.
The widespread deforestation and other environmental destruction in Sumatra and other parts of Indonesia has often been described by academics as an
ecocide
Ecocide (from Greek 'home' and Latin 'to kill') is the destruction of the natural environment, environment by humans. Ecocide threatens all human populations that are dependent on natural resources for maintaining Ecosystem, ecosystems and ensu ...
.
Etymology

Sumatra was known in ancient times by the
Sanskrit
Sanskrit (; stem form ; nominal singular , ,) is a classical language belonging to the Indo-Aryan languages, Indo-Aryan branch of the Indo-European languages. It arose in northwest South Asia after its predecessor languages had Trans-cultural ...
names of ('Island of Gold') and ('Land of Gold'), because of the gold deposits in the island's
highlands. The earliest known mention of the current form "Sumatra" was in 1017, when the
local
Local may refer to:
Geography and transportation
* Local (train), a train serving local traffic demand
* Local, Missouri, a community in the United States
Arts, entertainment, and media
* ''Local'' (comics), a limited series comic book by Bria ...
king
Haji Sumatrabhumi ("king of the land of Sumatra") sent an envoy to
China
China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...
.
Arab
Arabs (, , ; , , ) are an ethnic group mainly inhabiting the Arab world in West Asia and North Africa. A significant Arab diaspora is present in various parts of the world.
Arabs have been in the Fertile Crescent for thousands of years ...
geographers referred to the island as (''
Lamuri'', ''Lambri'' or ''Ramni'') in the tenth through thirteenth centuries, in reference to a kingdom near modern-day
Banda Aceh
Banda Aceh (; , Jawi script, Jawi: ) is the capital and largest city in the province of Aceh, Indonesia. It is located on the island of Sumatra and has an elevation of 35 metres. The city covers an area of and had a population of 223,446 peopl ...
which was the first landfall for traders. The island has also been known by other names, including ''Andalas'' or ''Percha Island''. Scholars suggest that mention of Suwarnadwipa in the Hindu Epic the ''
Ramayana
The ''Ramayana'' (; ), also known as ''Valmiki Ramayana'', as traditionally attributed to Valmiki, is a smriti text (also described as a Sanskrit literature, Sanskrit Indian epic poetry, epic) from ancient India, one of the two important epics ...
'' may be a reference to Sumatra. According to experts on ''
The Ramayana,'' the epic is one of the first sources to document the relationship between India and the Indonesian archipelago.
In the late 13th century,
Marco Polo
Marco Polo (; ; ; 8 January 1324) was a Republic of Venice, Venetian merchant, explorer and writer who travelled through Asia along the Silk Road between 1271 and 1295. His travels are recorded in ''The Travels of Marco Polo'' (also known a ...
referred to the kingdom as , while his contemporary fellow Italian traveller
Odoric of Pordenone
Odoric of Pordenone (c. 1280–14 January 1331) was a Franciscan friar and missionary explorer from Friuli in northeast Italy. He journeyed through India, Sumatra, Java, and China, where he spent three years in the imperial capital of Khanbaliq ...
used the form . Later in the 14th century the local form "Sumatra" became popular abroad due to the rising power of the kingdom of
Samudera Pasai
The Samudera Pasai Sultanate (), also known as Samudera or Pasai or Samudera Darussalam or Pacem, was a Muslim kingdom on the north coast of Sumatra from the 13th to the 16th centuries.
Little evidence has been left to allow for historical ...
and the subsequent
Sultanate of Aceh
The Sultanate of Aceh, officially the Kingdom of Aceh Darussalam (; Jawoë: ), was a sultanate centered in the modern-day Indonesian province of Aceh. It was a major regional power in the 16th and 17th centuries, before experiencing a long per ...
.
From then on, subsequent European writers mostly used ''Sumatra'' or similar forms of the name for the entire island.
History
By the year
692, the
Melayu Kingdom
The Melayu Kingdom (also known as Malayu, Dharmasraya Kingdom or the Jambi Kingdom; , reconstructed Middle Chinese pronunciation ''mat-la-yu kwok'')Muljana, Slamet , (2006), ''Sriwijaya'', Yogyakarta: LKIS, . was a classical Buddhist kingdom ...
was absorbed by
Srivijaya
Srivijaya (), also spelled Sri Vijaya, was a Hinduism, Hindu-Buddhism, Buddhist thalassocracy, thalassocratic empire based on the island of Sumatra (in modern-day Indonesia) that influenced much of Southeast Asia. Srivijaya was an important ...
.
Srivijaya's influence waned in the 11th century, specifically in the year 1025, after suffering defeat at the hands of the
Chola Empire
The Chola Empire, which is often referred to as the Imperial Cholas, was a medieval thalassocratic empire based in southern India that was ruled by the Chola dynasty, and comprised overseas dominions, protectorates and spheres of influence ...
in southern India
By the end of the 12th century, Srivijaya had been reduced to a kingdom, and its dominant role in South Sumatra ended with the last king, Ratu Sekekhummong, who founded the milestone of Kepaksian Sekala Brak in the 13th century AD with the Dalom building.
At the same time, the
spread of Islam in Indonesia occurred gradually and indirectly, starting from the western regions such as the Sumatra area which became the first place for the spread of Islam in the archipelago, then Java, then to the eastern regions of Indonesia, Sulawesi and Maluku.
The island of Sumatra is also an area in the archipelago that received the spread of Islam first compared to other islands or other areas.
The island of Sumatra became the first area to receive the spread of Islam because of the position of the island of Sumatra which is close to the Malacca strait.
The initial process of Islamization related to trade and also the formation of the kingdom.
Islam entered Sumatra through pious
Arabs
Arabs (, , ; , , ) are an ethnic group mainly inhabiting the Arab world in West Asia and North Africa. A significant Arab diaspora is present in various parts of the world.
Arabs have been in the Fertile Crescent for thousands of yea ...
and
Tamil
Tamil may refer to:
People, culture and language
* Tamils, an ethno-linguistic group native to India, Sri Lanka, and some other parts of Asia
**Sri Lankan Tamils, Tamil people native to Sri Lanka
** Myanmar or Burmese Tamils, Tamil people of Ind ...
traders in the 6th and 7th centuries AD. At the beginning and end of the 13th century the formation of the kingdom, the king of the
Samudra kingdom had converted to Islam.
Marco Polo
Marco Polo (; ; ; 8 January 1324) was a Republic of Venice, Venetian merchant, explorer and writer who travelled through Asia along the Silk Road between 1271 and 1295. His travels are recorded in ''The Travels of Marco Polo'' (also known a ...
visited the island in 1292, and his fellow Italian
Odoric of Pordenone
Odoric of Pordenone (c. 1280–14 January 1331) was a Franciscan friar and missionary explorer from Friuli in northeast Italy. He journeyed through India, Sumatra, Java, and China, where he spent three years in the imperial capital of Khanbaliq ...
in 1321.
Aceh in the north of Sumatra became known in the 16th century as trading centre for the
pepper trade by shipping quality
piperaceae
The Piperaceae (), also known as the pepper family, are a large family (biology), family of flowering plants. The group contains roughly 3,600 currently accepted species in five genera. The vast majority of species can be found within the two mai ...
(''pepper''). Aceh became the main commercial centre of the
Aceh Sultanate
The Sultanate of Aceh, officially the Kingdom of Aceh Darussalam (; Jawoë: ), was a sultanate centered in the modern-day Indonesian province of Aceh. It was a major regional power in the 16th and 17th centuries, before experiencing a long pe ...
and trading routes were established to the
Mediterranean
The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern ...
via the
Red Sea
The Red Sea is a sea inlet of the Indian Ocean, lying between Africa and Asia. Its connection to the ocean is in the south, through the Bab-el-Mandeb Strait and the Gulf of Aden. To its north lie the Sinai Peninsula, the Gulf of Aqaba, and th ...
to rival the Portuguese
shipping lanes. The reign of
Iskandar Muda is known as the ''golden age'' of Sumatra because he extended the cultural influence of the Aceh Sultanate to
Padang
Padang () is the Capital city, capital and largest city of the Indonesian Provinces of Indonesia, province of West Sumatra. It had a population of 833,562 at the 2010 CensusBiro Pusat Statistik, Jakarta, 2011. and 909,040 at the 2020 Census;Bad ...
and
Johor
Johor, also spelled Johore,'' is a States and federal territories of Malaysia, state of Malaysia in the south of the Malay Peninsula. It borders with Pahang, Malacca and Negeri Sembilan to the north. Johor has maritime borders with Singapore ...
. The Aceh Sultanate sustained the rivalry with the
Johor sultanate
The Johor Sultanate ( or ; also called the Sultanate of Johor, Johor-Pahang-Riau-Lingga, or the Johor Empire) was founded by Sultan of Malacca Mahmud Shah of Malacca, Mahmud Shah's son, Alauddin Riayat Shah II of Johor, Alauddin Riayat Shah ...
, the Dutch, and the Portuguese throughout the 16th and 17th century. When the Dutch were weakened in the 18th century the British empire began to actively intervene in Aceh, establishing close relations between Banda Aceh and
Penang
Penang is a Malaysian state located on the northwest coast of Peninsular Malaysia along the Strait of Malacca. It has two parts: Penang Island, where the capital city, George Town, is located, and Seberang Perai on the Malay Peninsula. Th ...
. In the 17th and 18th century the Aceh Sultanate battled the
Siak sultanate in the south of Sumatra. The port city of
Banda Aceh
Banda Aceh (; , Jawi script, Jawi: ) is the capital and largest city in the province of Aceh, Indonesia. It is located on the island of Sumatra and has an elevation of 35 metres. The city covers an area of and had a population of 223,446 peopl ...
was recorded in European historical writings since the 13th century. In terms of
economic development
In economics, economic development (or economic and social development) is the process by which the economic well-being and quality of life of a nation, region, local community, or an individual are improved according to targeted goals and object ...
the port of Banda Aceh only started to face competition in the 18th century when more ports were constructed in Sumatra for
maritime transport
Maritime transport (or ocean transport) or more generally waterborne transport, is the transport of people (passengers or goods (cargo) via waterways. Freight transport by watercraft has been widely used throughout recorded history, as it pr ...
. Nevertheless, major pepper suppliers used the port of Banda Aceh at the beginning of the 19th century. The port in
Medan
Medan ( , ) is the capital city, capital and largest city of the Indonesian Provinces of Indonesia, province of North Sumatra. The nearby Strait of Malacca, Port of Belawan, and Kualanamu International Airport make Medan a regional hub and multi ...
grew swiftly in the late 19th and early 20th century. Meanwhile the medium sized port of
Palembang
Palembang (, Palembang: ''Pelémbang'', Mandarin: 巨港 (Jùgǎng), Hokkien: 舊港 (Kū-káng), Jawi: ) is the capital city of the Indonesian province of South Sumatra. The city proper covers on both banks of the Musi River in the ea ...
faced a stiff economic decline as the heritage of the Srivijaya empire was superseded by the
economic policy
''Economic Policy'' is a quarterly peer-reviewed academic journal published by Oxford University Press, Oxford Academic on behalf of the Centre for Economic Policy Research, the Center for Economic Studies (University of Munich), and the Paris Scho ...
of the
Singhasari
Singhasari ( or , ), also known as Tumapel, was a Javanese people, Javanese Hindu-Buddist empires, Hindu-Buddhist Monarchy, kingdom located in east Java (island), Java between 1222 and 1292. The kingdom succeeded the Kingdom of Kediri as th ...
and
Majapahit
Majapahit (; (eastern and central dialect) or (western dialect)), also known as Wilwatikta (; ), was a Javanese people, Javanese Hinduism, Hindu-Buddhism, Buddhist thalassocracy, thalassocratic empire in Southeast Asia based on the island o ...
. The
Palembang sultanate experienced a terminal decline in the early 19th century.
With the coming of the
Dutch Empire
The Dutch colonial empire () comprised overseas territories and trading posts under some form of Dutch control from the early 17th to late 20th centuries, including those initially administered by Dutch chartered companies—primarily the Du ...
, the many Sumatran princely states gradually fell under their control. Aceh posed major obstacles, as the Dutch were involved in the long and costly
Aceh War
The Aceh War (), also known as the Dutch War or the Infidel War (1873–1904), was an armed military conflict between the Sultanate of Aceh and the Kingdom of the Netherlands which was triggered by discussions between representatives of Aceh ...
(1873–1903).
During the
Second World War
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
,
Japan invaded Sumatra in 1942.
The
Free Aceh Movement
The Free Aceh Movement (, GAM; ) was a separatism, separatist group seeking independence for the Aceh region of Sumatra, Indonesia. GAM fought against Indonesian government forces in the Insurgency in Aceh, Aceh insurgency from 1976 to 2005. E ...
fought against Indonesian government forces in the
Aceh Insurgency from 1976 to 2005. Security crackdowns in 2001 and 2002 resulted in several thousand civilian deaths.
The island was heavily impacted by both the 1883
Krakatoa eruption and the 2004
Boxing Day Tsunami.
Demographics
Sumatra's population as of 2023 was estimated to be about 60,795,669 ; it has about the same number of inhabitants as
South Africa
South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...
, making it the
fifth-most populous island in the world. Yet because it is such a large island, it is not densely populated: it has an average of about 126 people per km
2.
Ethnic groups
The largest indigenous ethnic groups in Sumatra are Malays, Minangkabaus, Bataks, Acehnese, and Lampungs. Other major non-indigenous ethnic groups are
Javanese,
Sundanese, and
Chinese.
Below are 11 largest ethnic groups in Sumatra based on the 2010 census (including
Riau Islands
The Riau Islands () is a provinces of Indonesia, 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 capit ...
,
Bangka Belitung,
Nias
Nias (, Nias: ''Tanö Niha'') is an island located off the western coast of Sumatra, Indonesia. Nias is also the name of the archipelago () of which the island is the centre, but also includes the Batu Islands to the southeast and the small ...
,
Mentawai,
Simeulue and islands around it)
Languages
There are over 52
languages
Language is a structured system of communication that consists of grammar and vocabulary. It is the primary means by which humans convey meaning, both in spoken and signed forms, and may also be conveyed through writing. Human language is ch ...
spoken, all of which (except Chinese and Tamil) belong to the
Malayo-Polynesian
The Malayo-Polynesian languages are a subgroup of the Austronesian languages, with approximately 385.5 million speakers. The Malayo-Polynesian languages are spoken by the Austronesian peoples outside of Taiwan, in the island nations of Southeast ...
branch of the
Austronesian language family. Within Malayo-Polynesian, they are divided into several sub-branches:
Chamic (which are represented by
Acehnese in which its closest relatives are languages spoken by
Ethnic Chams in Cambodia and Vietnam),
Malayic (
Malay,
Minangkabau and other closely related languages),
Northwest Sumatra–Barrier Islands (
Batak languages,
Gayo and others),
Lampungic (includes Proper Lampung and
Komering) and
Bornean (represented by
Rejang in which its closest linguistic relatives are
Bukar Sadong and
Land Dayak spoken in
West Kalimantan
West Kalimantan () is a province of Indonesia. It is one of five Indonesian provinces comprising Kalimantan, the Indonesian part of the island of Borneo. Its capital and largest city is Pontianak. It is bordered by East Kalimantan and Central ...
and
Sarawak
Sarawak ( , ) is a States and federal territories of Malaysia, state of Malaysia. It is the largest among the 13 states, with an area almost equal to that of Peninsular Malaysia. Sarawak is located in East Malaysia in northwest Borneo, and is ...
(
Malaysia
Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...
)). Northwest Sumatra–Barrier Islands and Lampungic branches are endemic to the island. Like all parts of Indonesia,
Indonesian (which was based on Riau Malay) is the official language and the main lingua franca. Although Sumatra has its own local lingua franca,
variants of Malay like Medan Malay and
Palembang Malay are popular in North and South Sumatra, especially in urban areas. Minangkabau (Padang dialect) is popular in West Sumatra, some parts of North Sumatra, Bengkulu, Jambi and Riau (especially in
Pekanbaru
Pekanbaru is the capital city of the Indonesian province of Riau, and a major economic center on the eastern side of Sumatra, Sumatra Island with its name derived from the Malay language, Malay (Indonesian language, Indonesian) word for 'new mar ...
and areas bordered with
West Sumatra
West Sumatra () is a Provinces of Indonesia, 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 ...
) while Acehnese is also used as an inter-ethnic means of communication in some parts of Aceh province.
Religion
The majority of people in Sumatra are Muslims (87.12%), while 10.69% are Christians, and less than 2.19% are Buddhists and Hindus.
Administration
Sumatra is one of seven geographical
regions of Indonesia
This is a list of some of the regions of Indonesia. Many regions are defined in law or regulations by the central government. At different times of Indonesia's history, the nation has been designated as having regions that do not necessarily cor ...
, which includes its adjacent smaller islands. Sumatra was one of the eight original
provinces of Indonesia
Provinces are the first-level administrative divisions of Indonesia. They were formerly called first-level provincial regions (), before the Post-Suharto era in Indonesia, Reform era. Provinces have a local government, consisting of a
List of ...
between 1945 and 1948. Including adjacent archipelagoes normally included with Sumatra (such as the Riau Islands, Nias and the Bangka-Belitung group), it now covers ten of Indonesia's
38 provinces, which are set out below with their areas and populations.
Geography

The longest axis of the island runs approximately northwest–southeast, crossing the equator near the centre. At its widest point, the island spans . The interior of the island is dominated by two geographical regions: the
Barisan Mountains
The Bukit Barisan or the Barisan Mountains are a mountain range on the western side of Sumatra, Indonesia, covering nearly 1,700 km (1,050 mi) from the north to the south of the island. The Bukit Barisan range consists primarily of volca ...
in the west and swampy plains in the east. Sumatra is the closest Indonesian island to mainland Asia.
To the southeast is
Java
Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...
, separated by the
Sunda Strait
The Sunda Strait () is the strait between the Indonesian islands of Java island, Java and Sumatra. It connects the Java Sea with the Indian Ocean.
Etymology
The strait takes its name from the Sunda Kingdom, which ruled the western portion of Ja ...
. To the north is the
Malay Peninsula
The Malay Peninsula is located in Mainland Southeast Asia. The landmass runs approximately north–south, and at its terminus, it is the southernmost point of the Asian continental mainland. The area contains Peninsular Malaysia, Southern Tha ...
(located on the Asian mainland), separated by the
Strait of Malacca
The Strait of Malacca is a narrow stretch of water, long and from wide, between the Malay Peninsula to the northeast and the Indonesian island of Sumatra to the southwest, connecting the Andaman Sea (Indian Ocean) and the South China Sea (Pa ...
. To the east is
Borneo
Borneo () is the List of islands by area, third-largest island in the world, with an area of , and population of 23,053,723 (2020 national censuses). Situated at the geographic centre of Maritime Southeast Asia, it is one of the Greater Sunda ...
, across the
Karimata Strait. West of the island is the
Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...
.
Sumatra is a highly seismic island. The
Great Sumatran fault (a
strike-slip
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...
fault), and the
Sunda megathrust (a
subduction zone
Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second p ...
), run the entire length of the island along its west coast. Huge earthquakes have been recorded throughout history. In 1797, an 8.9 earthquake shook Western Sumatra, and in 1833, a 9.2 earthquake shook Bengkulu and Western Sumatra. Both events caused large
tsunami
A tsunami ( ; from , ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions (including detonations, ...
s. Earthquakes are very common throughout the coastal area of the west and center of the island, and tsunamis are common due to the high seismicity in the area.
On 26 December 2004, the western coast and islands of Sumatra, particularly
Aceh
Aceh ( , ; , Jawi script, Jawoë: ; Van Ophuijsen Spelling System, Old Spelling: ''Atjeh'') is the westernmost Provinces of Indonesia, province of Indonesia. It is located on the northern end of Sumatra island, with Banda Aceh being its capit ...
province, were struck by a
tsunami
A tsunami ( ; from , ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions (including detonations, ...
following the
Indian Ocean earthquake. This was the longest earthquake recorded, lasting between 500 and 600 seconds (8.33–10 minutes). More than 170,000 Indonesians were killed, primarily in Aceh. Other recent earthquakes to strike Sumatra include the
2005 Nias–Simeulue earthquake
The 2005 Nias–Simeulue earthquake occurred on 28 March off the west coast of northern Sumatra, Indonesia in the subduction zone of the Sunda megathrust. At least 915 people were killed, mostly on the island of Nias. It was among the top 10 mos ...
and the
2010 Mentawai earthquake and tsunami
The 2010 Mentawai earthquake occurred with a Moment magnitude scale, moment magnitude of 7.8 on 25 October off the western coast of Sumatra at 21:42 local time (14:42 UTC). The earthquake occurred on the same fault that produced the 2004 Indian O ...
.
Lake Toba is the site of a
supervolcanic eruption that occurred around 74,000 years ago, representing a climate-changing event. The most important rivers in Sumatra belong to the catchment area of the
South China Sea
The South China Sea is a marginal sea of the Western Pacific Ocean. It is bounded in the north by South China, in the west by the Indochinese Peninsula, in the east by the islands of Taiwan island, Taiwan and northwestern Philippines (mainly Luz ...
. Heading north to south, the
Asahan,
Rokan,
Siak,
Kampar,
Indragiri,
Batanghari flow into the
Malacca Strait
The Strait of Malacca is a narrow stretch of water, long and from wide, between the Malay Peninsula to the northeast and the Indonesian island of Sumatra to the southwest, connecting the Andaman Sea (Indian Ocean) and the South China Sea (Pa ...
, while the island's largest river, the
Musi, flows into the sea at
Bangka Strait
Bangka Strait is the strait that separates the island of Sumatra from Bangka Island () in the Java Sea, Indonesia
Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, India ...
in the south. To the east, big rivers carry silt from the mountains, forming the vast lowland interspersed by swamps. Even if mostly unsuitable for farming, the area is currently of great economic importance for Indonesia. It produces oil from both above and below the soil –
palm oil
Palm oil is an edible vegetable oil derived from the mesocarp (reddish pulp) of the fruit of oil palms. The oil is used in food manufacturing, in beauty products, and as biofuel. Palm oil accounted for about 36% of global oils produced from o ...
and
petroleum
Petroleum, also known as crude oil or simply oil, is a naturally occurring, yellowish-black liquid chemical mixture found in geological formations, consisting mainly of hydrocarbons. The term ''petroleum'' refers both to naturally occurring un ...
.
Sumatra is the largest producer of
Indonesian coffee
Indonesia was the fourth-largest producer of coffee in the world in 2014.[Production](_blank)
ico.org Coffee ...
. Small-holders grow Arabica coffee (''
Coffea arabica
''Coffea arabica'' (), also known as the Arabica coffee, is a species of flowering plant in the coffee and madder family Rubiaceae. It is believed to be the first species of coffee to have been cultivated and is the dominant cultivar, represe ...
'') in the highlands, while Robusta (''
Coffea canephora
''Coffea canephora'' (especially ''C. canephora var. robusta'', so predominantly cultivated that it is often simply termed ''Coffea robusta'', or commonly robusta coffee) is a species of coffee plant that has its origins in central and weste ...
'') is found in the lowlands. Arabica coffee from the regions of Gayo, Lintong and Sidikilang is typically processed using the
Giling Basah (wet hulling) technique, which gives it a heavy body and low acidity.
By population, Medan is the largest city in Sumatra.
[Biro Pusat Statistik, Jakarta.] Medan is also the most visited and developed city in Sumatra.
Largest cities
Flora and fauna

Sumatra supports a wide range of vegetation types that are home to a rich variety of species, including 17 endemic genera of plants.
Unique species include the
Sumatran pine which dominates the
Sumatran tropical pine forests of the higher mountainsides in the north of the island and rainforest plants such as ''
Rafflesia arnoldii
''Rafflesia arnoldii'', the corpse flower, or giant padma, Its local name is Petimum Sikinlili. It is a species of flowering plant in the parasitic genus '' Rafflesia'' within the family Rafflesiaceae. It is noted for producing the largest in ...
'' (the world's largest individual flower), and the
titan arum (the world's largest unbranched
inflorescence
In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...
).
The island is home to 201 mammal species and 580 bird species. There are nine endemic mammal species on mainland Sumatra and 14 more endemic to the nearby
Mentawai Islands
Mentawai may refer to:
* Mentawai Islands, Indonesia
** Mentawai Strait
** Mentawai people, ethnic group of Indonesia
** Mentawai language, their Austronesian language
{{dab
Language and nationality disambiguation pages ...
.
There are about 300 freshwater fish species in Sumatra. There are 93
amphibian species in Sumatra, 21 of which are endemic to Sumatra.
The
Sumatran tiger
The Sumatran tiger is a population of ''Panthera tigris sondaica'' on the Indonesian island of Sumatra. It is the only surviving tiger population in the Sunda Islands, where the Bali tiger, Bali and Javan tigers are extinct.
DNA sequencing, Sequ ...
,
Sumatran rhinoceros
The Sumatran rhinoceros (''Dicerorhinus sumatrensis''), also known as the Sumatran rhino, hairy rhinoceros or Asian two-horned rhinoceros, is a rare member of the family Rhinocerotidae and one of five extant species of rhinoceros; it is the o ...
,
Sumatran elephant,
Sumatran ground cuckoo,
Sumatran orangutan
The Sumatran orangutan (''Pongo abelii'') is one of the three species of orangutans. Critically endangered, and found only in the north of the Indonesian island of Sumatra, it is rarer than the Bornean orangutan but more common than the recently ...
and
Tapanuli orangutan are all critically endangered, indicating the highest level of threat to their survival. In October 2008, the Indonesian government announced a plan to protect Sumatra's remaining forests.
The island includes more than 10 national parks, including three which are listed as the
Tropical Rainforest Heritage of Sumatra World Heritage Site
World Heritage Sites are landmarks and areas with legal protection under an treaty, international treaty administered by UNESCO for having cultural, historical, or scientific significance. The sites are judged to contain "cultural and natural ...
–
Gunung Leuser National Park,
Kerinci Seblat National Park and
Bukit Barisan Selatan National Park. The
Berbak National Park is one of three national parks in Indonesia listed as a
wetland
A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...
of international importance under the
Ramsar Convention
The Ramsar Convention on Wetlands of International Importance Especially as Waterfowl Habitat is an international treaty for the conservation and sustainable use of Ramsar site, Ramsar sites (wetlands). It is also known as the Convention on We ...
.
Sumatra has lost almost 50% of its tropical rainforest since 1980. Many species are now
critically endangered
An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...
, such as the
Sumatran ground cuckoo, the
Sumatran tiger
The Sumatran tiger is a population of ''Panthera tigris sondaica'' on the Indonesian island of Sumatra. It is the only surviving tiger population in the Sunda Islands, where the Bali tiger, Bali and Javan tigers are extinct.
DNA sequencing, Sequ ...
, the
Sumatran elephant, the
Sumatran rhinoceros
The Sumatran rhinoceros (''Dicerorhinus sumatrensis''), also known as the Sumatran rhino, hairy rhinoceros or Asian two-horned rhinoceros, is a rare member of the family Rhinocerotidae and one of five extant species of rhinoceros; it is the o ...
, and the
Sumatran orangutan
The Sumatran orangutan (''Pongo abelii'') is one of the three species of orangutans. Critically endangered, and found only in the north of the Indonesian island of Sumatra, it is rarer than the Bornean orangutan but more common than the recently ...
.
Deforestation
Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. Ab ...
on the island has also resulted in serious seasonal smoke haze over neighbouring countries, such as the
2013 Southeast Asian haze which caused considerable tensions between Indonesia and affected countries
Malaysia
Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...
and
Singapore
Singapore, officially the Republic of Singapore, is an island country and city-state in Southeast Asia. The country's territory comprises one main island, 63 satellite islands and islets, and one outlying islet. It is about one degree ...
.
The widespread deforestation and other environmental destruction in Sumatra and other parts of Indonesia has often been described by academics as an
ecocide
Ecocide (from Greek 'home' and Latin 'to kill') is the destruction of the natural environment, environment by humans. Ecocide threatens all human populations that are dependent on natural resources for maintaining Ecosystem, ecosystems and ensu ...
.
Rail transport
Several unconnected railway networks built during
Netherlands East Indies
The Dutch East Indies, also known as the Netherlands East Indies (; ), was a Dutch Empire, Dutch colony with territory mostly comprising the modern state of Indonesia, which Proclamation of Indonesian Independence, declared independence on 17 Au ...
exist in Sumatra, such as the ones connecting
Banda Aceh
Banda Aceh (; , Jawi script, Jawi: ) is the capital and largest city in the province of Aceh, Indonesia. It is located on the island of Sumatra and has an elevation of 35 metres. The city covers an area of and had a population of 223,446 peopl ...
-
Lhokseumawe
Lhokseumawe (; , Jawi script, Jawoë: ), is the second largest city (by population, after Bandar Aceh, Banda Aceh) in Aceh province, Indonesia, having recently overtaken Langsa. The city covers an area of 181.06 square kilometres, and had a popu ...
-
Besitang-
Medan
Medan ( , ) is the capital city, capital and largest city of the Indonesian Provinces of Indonesia, province of North Sumatra. The nearby Strait of Malacca, Port of Belawan, and Kualanamu International Airport make Medan a regional hub and multi ...
-
Tebingtinggi-
Pematang Siantar-
Rantau Prapat in Northern Sumatra (the Banda Aceh-Besitang section was closed in 1971, but is currently being rebuilt).
Padang
Padang () is the Capital city, capital and largest city of the Indonesian Provinces of Indonesia, province of West Sumatra. It had a population of 833,562 at the 2010 CensusBiro Pusat Statistik, Jakarta, 2011. and 909,040 at the 2020 Census;Bad ...
-
Solok-
Bukittinggi
Bukittinggi (, Jawi script, Jawi: , formerly ) is the third largest city in West Sumatra, Indonesia, with a population of 111,312 in 2010Biro Pusat Statistik, Jakarta, 2011. and 121,028 in 2020.Badan Pusat Statistik, Jakarta, 2021. An official es ...
in
West Sumatra
West Sumatra () is a Provinces of Indonesia, 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 ...
, and
Bandar Lampung-
Palembang
Palembang (, Palembang: ''Pelémbang'', Mandarin: 巨港 (Jùgǎng), Hokkien: 舊港 (Kū-káng), Jawi: ) is the capital city of the Indonesian province of South Sumatra. The city proper covers on both banks of the Musi River in the ea ...
-
Lahat
The LAHAT (laser homing attack or laser homing anti-tank, also a Hebrew word for ''incandescence'') is a third generation semi-active laser homing low-weight anti-tank guided missile developed since 1991 and manufactured by Israel Aerospace In ...
-
Lubuklinggau in Southern Sumatra.
See also
*
Architecture of Sumatra
*
Bukit Seguntang
*
Communism in Sumatra
*
Music of Sumatra
Notes
References
Further reading
*
* William Marsden
''The History of Sumatra'' (1783); 3rd ed. (1811) freely available online.
External links
*
{{Authority control
Greater Sunda Islands
Maritime Southeast Asia
Islands of the Indian Ocean
Populated places in Indonesia
Islands of Indonesia