Sumatra

Sumatra is one of the Sunda Islands in western Indonesia. It is the largest island that is completely part of Indonesia and the sixth-largest island in the whole world. Sumatra covers an area of 482,286.55 km² (182,812 mi.²), including nearby islands such as Simeulue, Nias, the Mentawai Islands, Enggano, the Riau Islands, Bangka and Belitung, and the Krakatoa archipelago.

The island stretches from northwest to southeast. The Indian Ocean lies along its northwest, west, and southwest coasts, while islands like Simeulue, Nias, Mentawai, and Enggano sit off the western shore. To the northeast, the narrow Strait of Malacca separates Sumatra from the Malay Peninsula, and to the southeast, the Sunda Strait separates it from Java. The Bukit Barisan mountains run along the center of the island, and the climate is tropical, hot, and humid. Once covered in lush tropical rain forest, Sumatra now faces serious environmental challenges.

Etymology

Sumatra has had many names throughout history. In ancient times, it was called Svarṇadvīpa ('Island of Gold') and Svarṇabhūmi ('Land of Gold') because of the gold found in its highlands. The name "Sumatra" was first recorded in 1017 when a local king sent an envoy to China. Arab traders called the island Ramni and later Lamuri, referring to a kingdom near present-day Banda Aceh. Other names included Andalas and Percha Island. Famous travelers like Marco Polo called the island Samara, and later it became known as Sumatra, especially with the rise of the Samudera Pasai kingdom and the Sultanate of Aceh.

History

The Muaro Jambi Temple Compounds are some of the largest and best-preserved ancient temples in Southeast Asia, built by the Melayu Kingdom.

By the year 692 CE, the Melayu Kingdom became part of the Srivijaya kingdom. Later, in 1025, the Chola Empire from India defeated Srivijaya. Islam began spreading in Sumatra through traders from Arab and Tamil backgrounds during the 6th and 7th centuries. By the 13th century, the king of the Samudra kingdom had converted to Islam. Famous travelers like Marco Polo visited in 1292, and Odoric of Pordenone came in 1321.

In the 16th century, Aceh became an important trading place for pepper. The Aceh Sultanate grew strong and influenced areas like Padang and Johor. Over time, it faced rivals such as the Johor sultanate, the Dutch, and the Portuguese. The port of Banda Aceh has been important since the 13th century.

When the Dutch Empire arrived, many areas of Sumatra came under their control, though Aceh resisted for a long time during the Aceh War from 1873 to 1903.

During the Second World War, Japan invaded Sumatra in 1942. The island also felt the effects of the 1883 Krakatoa eruption and the 2004 Indian Ocean earthquake and tsunami.

Demographics

As of mid-2025, Sumatra's population was estimated to be about 62,259,500 people. This is roughly the same number of people as in South Africa, making Sumatra the fifth-most populous island in the world. Even though it has many people, Sumatra is a very large island, so it is not crowded. On average, there are about 129 people living in each square kilometer.

Historical population
Year	Pop.	±%
1971	20,808,148	—
1980	28,016,160	+34.6%
1990	36,506,703	+30.3%
1995	40,830,334	+11.8%
2000	42,616,164	+4.4%
2005	45,839,041	+7.6%
2010	50,613,947	+10.4%
2015	55,198,752	+9.1%
2020	58,557,211	+6.1%
2025	62,259,500	+6.3%
sources:

Ethnic groups

Sumatra is home to many different groups of people. Some of the largest groups include Malays, Minangkabaus, Bataks, Acehnese, and Lampungs. There are also many people from other places, such as Javanese, Sundanese, and Chinese.

People in Sumatra speak over 52 different languages. Most of these languages belong to a big family called Austronesian. The main language used everywhere is Indonesian, but there are also many local languages used in different areas.

Languages

Religion

Kedukan Bukit Inscription, using Pallava alphabet, is the oldest surviving specimen of the Old Malay language in South Sumatra, Indonesia.

Most people in Sumatra follow the religion of Islam. There are also many Protestant and Roman Catholic Christians, as well as some people who follow Buddhism and Hinduism.

Ethnic groups	Population
Javanese	15,239,275
Bataks	7,302,330
Minangkabau	5,799,001
Ethnic groups from South Sumatra	4,826,272
Malays	4,016,182
Ethnic groups from Aceh	3,991,883
Ethnic groups from Jambi	1,379,351
Sundanese	1,231,888
Ethnic groups from Lampung	1,109,601
Nias	1,021,267
Other	2,086,804

Religions	Total
Islam	53,409,001
Protestantism	5,592,010
Roman Catholicism	1,023,603
Buddhism	832,415
Hinduism	193,917
Confucianism	37,214
Aliran Kepercayaan	10,893
Overall	61,099,053

Administration

Sumatra and its nearby smaller islands make up one of the seven main areas of Indonesia. From 1945 to 1948, Sumatra was one of Indonesia’s eight original provinces. Today, including nearby island groups like the Riau Islands Province, Nias Island, and the Bangka-Belitung group, Sumatra includes ten of Indonesia’s 38 provinces.

Provinces within the region of Sumatra
Name	Area (km²)	Population census 2000	Population census 2010	Population census 2015	Population census 2020	Population estimate 2025	Capital
Aceh	58,485.90	4,073,006	4,486,570	4,993,385	5,274,871	5,626,000	Banda Aceh
North Sumatra	72,460.74	11,642,488	12,326,678	13,923,262	14,799,361	15,785,800	Medan
West Sumatra	42,119.54	4,248,515	4,846,909	5,190,577	5,534,472	5,914,300	Padang
Riau	89,935.90	3,907,763	5,543,031	6,330,941	6,394,097	6,811,200	Pekanbaru
Riau Islands	8,269.71	1,040,207	1,685,698	1,968,313	2,064,564	2,213,500	Tanjung Pinang
Jambi	49,026.58	2,407,166	3,088,618	3,397,164	3,548,228	3,768,500	Jambi
South Sumatra	91,592.43	6,210,800	7,446,401	8,043,042	8,467,432	8,928,500	Palembang
Bengkulu	20,130.21	1,455,500	1,713,393	1,872,136	2,010,670	2,138,000	Bengkulu
Lampung	33,575.41	6,730,751	7,596,115	8,109,601	9,007,848	9,522,900	Bandar Lampung
Bangka Belitung	16,690.13	899,968	1,223,048	1,370,331	1,455,678	1,550,800	Pangkal Pinang
Totals	482,286.55	42,616,164	50,613,947	55,198,752	58,557,211	62,259,500

Geography

The island of Sumatra stretches about 1,790 kilometers (1,110 miles) from northwest to southeast. At its widest point, it spans 435 kilometers (270 miles). The west side of Sumatra has tall mountains called the Barisan Mountains, while the east is made up of flat, swampy lands. Sumatra is the closest Indonesian island to Asia.

Map of geological formation of Sumatra island

Sumatra sits near several bodies of water. To the southeast is Java, separated by the Sunda Strait. To the north is the Malay Peninsula, separated by the Strait of Malacca. To the east lies Borneo across the Karimata Strait, and to the west is the Indian Ocean.

Sumatra has many rivers. Some flow into the Malacca Strait, while the largest river, the Musi, flows into the Bangka Strait. The island is also known for its coffee, especially Arabica coffee grown in the highlands.

Largest cities

Medan, the largest city in Sumatra

Medan is the biggest city on Sumatra. It is also the most popular and developed city there.

Rank	City	Province	City Birthday	Area (in km²)	Population 2010 census	Population 2020 census
1	Medan	North Sumatra	1 July 1590	265.10	2,097,610	2,435,252
2	Palembang	South Sumatra	17 June 683	400.61	1,455,284	1,668,848
3	Bandar Lampung	Lampung	17 June 1682	169.21	881,801	1,166,066
4	Pekanbaru	Riau	23 June 1784	633.01	897,767	983,356
5	Padang	West Sumatra	7 August 1669	694.96	833,562	909,040
6	Jambi	Jambi	17 May 1946	205.00	531,857	606,200
7	Bengkulu	Bengkulu	18 March 1719	144.52	308,544	373,591
8	Dumai	Riau	20 April 1999	2,039.35	253,803	316,782
9	Binjai	North Sumatra		90.24	246,154	291,842
10	Pematang Siantar	North Sumatra	24 April 1871	60.52	234,698	268,254
11	Banda Aceh	Aceh	22 April 1205	61.36	223,446	252,899
12	Lubuklinggau	South Sumatra	17 August 2001	419.80	201,308	234,166

Flora and fauna

Sumatran tiger

Sumatra has many different kinds of plants and animals. Some special plants include the Sumatran pine and huge flowers like Rafflesia arnoldii. The island is home to many animals, such as the Sumatran tiger, Sumatran rhinoceros, Sumatran elephant, and Sumatran orangutan. These animals are in danger because their homes are being lost.

Sumatra has many national parks to help protect its nature, including the Tropical Rainforest Heritage of Sumatra World Heritage Site. However, many forests have been cut down, which harms both the animals and the environment.

Rail transport

Sumatra has several old railway lines that were built when it was part of the Netherlands East Indies. These railways connect places like Banda Aceh to Medan in the north, Padang to Bukittinggi in the west, and Bandar Lampung to Palembang in the south. Some parts of these railways, like the one between Banda Aceh and Besitang, closed long ago but are now being rebuilt.