East Kalimantan (Indonesian: , abbreviated as Kaltim) is a province of Indonesia. Its territory comprises the eastern portion of Borneo/Kalimantan. It had a population of about 3.03 million at the 2010 census (within the present boundary), and 3.766 million at the 2020 census; the official estimate in mid-2025 was 4,267,600. Its capital is Samarinda, the most populous city on the entire island of Borneo.
East Kalimantan has a total area of and is the third least densely populated province in Kalimantan (after North Kalimantan and Central Kalimantan). The majority of the region shares a maritime border to the east with West Sulawesi and Central Sulawesi; its Cape Mangkalihat separates the Makassar Strait from the Celebes Sea. Its former northernmost region was split off on 25 October 2012 and is now the separate province of North Kalimantan; meanwhile it still shares land border to the west with West Kalimantan and Central Kalimantan; to its south, East Kalimantan borders South Kalimantan. The province bordered Sabah, Malaysia before the creation of North Kalimantan, and still has a short border with Sarawak, Malaysia through Mahakam Ulu Regency.
Since 11 January 2013, East Kalimantan has been divided into seven regencies and three cities. The proposed capital city of Indonesia, Nusantara, is currently constructed entirely within the province.
History
Prehistory
thumb|left|214x214px|One of the oldest known [[Figurative art|figurative paintings, a depiction of a bull, was discovered in the Lubang Jeriji Saléh cave dated as over 40,000 (perhaps as old as 52,000) years old. The cave paintings were first spotted in 1994 by the French explorer Luc-Henri Fage and the French archaeologist Jean-Michel Chazine, from Kalimanthrope. In 2018, a team of scientists investigating the cave, led by Maxime Aubert from Griffith University and Pindi Setiawan from the Bandung Institute of Technology, published a report in the journal Nature identifying the paintings as the world's oldest known figurative art. The team had previously investigated cave paintings in the neighbouring island of Sulawesi. In order to date the paintings, the team used dating techniques on the calcium carbonate (limestone) deposits close to them.
4th to 17th centuries
frame|right|The ancient [[Yūpa#Yūpa inscription in Indonesia|Yūpa inscription of Mulavarman, king of Kutai Martadipura dating back to the 4th century CE discovered in present Muara Kaman area, Kutai Kartanegara Regency]]
East Kalimantan has been home to several kingdoms, such as the first and oldest Hindu kingdom of Indonesia, the Kingdom of Kutai Martadipura founded in the 4th century CE. It was succeeded by the Sultanate of Kutai ing Martadipura in the 14th century. Other kingdoms were also located in East Kalimantan, such as the Sultanate of Pasir. East Kalimantan region includes Pasir, Kutai, Berau and also Karasikan (Buranun / pre-Sultanate of Sulu) claimed as conquered territory Suryanata Maharaja, the governor of Majapahit in the State Dipa, located in the Great Temple in Amuntai, until 1620 in the Sultanate of Banjar. However, in the Chinese History Annals, Ming shi 明史, at 1417, some parts of the eastern Kalimantan were recorded as a kingdom under the rule of the Philippine kingdom of then Hindu Sulu, as Kalimantan was ruled by a Sulu monarch named Mahalatu Gelamading (Maharaja Klainbantangan) whose title, Klainbantangan, in Chinese rendering, was named after his territory Kalimantan. At this point in time, Sulu had rebelled against Majapahit rule and had invaded Northeast and East Borneo all the way to the territory of Kalimantan. Between the years 1620–1624, kingdoms in East Kalimantan fell under the influence of the Sultanate of Sultan Alauddin Makassar, before the Bungaya agreement. According to the Hikayat Banjar, the Sultan of Makassar never borrowed land for trade covers an area east and southeast of Borneo to the Sultan Mustain Billah of Banjar when Kiai Martasura sent to Makassar and entered into an agreement with the Sultan Tallo I Mangngadaccinna Daeng I Ba'le 'Sultan Mahmud Karaeng Pattingalloang, who became Mangkubumi and principal advisor to the Sultan Muhammad Said, king of Gowa in 1638–1654 and also in-law of Sultan Hasanuddin, who established the East Kalimantan region as a place to trade for the Sultanate of Makassar (Gowa-Tallo); since then people began to arrive from South Sulawesi. However, based on the agreement between the Sultanate of Banjar and the Dutch East India Company (VOC) in 1635, VOC helped Banjar restore lands in East Kalimantan to the sphere of influence of the Sultanate of Banjar. It was set out in the Bungaya agreement that the Sultanate of Makassar was not allowed to trade up to the east and the north Borneo.
19th to 20th centuries
thumb|The map of East Kalimantan before 2012, featuring 14 regencies and cities. This map since then still oversees occasional usage, even though it has become outdated for more than a decade.
In accordance with treaties, on January 1, 1817, Sultan Sulaiman of Banjar handed East Kalimantan, Central Kalimantan, part of West and South Kalimantan (including Banjarmasin) over to the Dutch East Indies. On May 4, 1826, Sultan Adam al-wathiq Billah of Banjar reaffirmed the handover of these territories to the Dutch East Indies colonial administration. In 1846, the Dutch began to put a Resident Assistant in East Borneo at Samarinda (now the province of East Kalimantan and the eastern part of South Kalimantan) named H. Von Dewall. Like all other Indonesian provinces, East Kalimantan was then part of the Dutch East Indies.
East Kalimantan with its then administrative area was established based on the Law No. 25 of 1956, originally only consisted of three regency-level special regions: Berau, Bulongan, and Kutai; Since late 1990s, the number of regencies and cities in East Kalimantan had steadily increased into 14 (with the last creation prior the creation of North Kalimantan, was being Tana Tidung Regency in 2007).
Splitting off North Kalimantan province
North Kalimantan was formally inaugurated as the 34th province of Indonesia on April 15, 2013. The new province was previously part of East Kalimantan Province.
New national capital
The province will host the future capital city of Indonesia that will be built on parts of Penajam North Paser and Kutai Kartanegara Regency. The future capital is to be named Nusantara, with construction originally projected to start in 2020, and intended to conclude in 2024. However, at a hearing before Committee V of Indonesia's House of Representatives on 9 June 2020, a government representative asserted that the government had not allocated the 2022 budget for the project (for 2022, the ministry proposed a budget worth over 100.46 trillion rupiah - over 7 billion US$ - a steep reduction from the figure of 149.81 trillion rupiah in 2021). Earlier, the National Planning Development Authority had said that the total sum needed to move the capital from its current location in Jakarta to East Kalimantan province amounted to 486 trillion rupiah, of which 265.2 trillion will be mobilised through the public-private partnership (PPP), 127.3 trillion from private special funds, and 93.5 trillion from the state budget. But the Ministry of Finance said that the government switched its priorities to mitigating the effect of the COVID-19 pandemic. The ministry announced that it had not allocated budget for the new capital project. Nevertheless, the new national capital was formally inaugurated in August 2024.
Geography
East Kalimantan Province comprises a land area of 125,336.81 square kilometers and a comprehensive ocean management area of 25,656 km<sup>2</sup>, located between 113°44'E and 119°00'E, and between 2°33'N and 2°25'S. The province is divided into seven regencies (kabupaten) and three cities (kota), together subdivided into 105 districts (kecamatan) and then into 1,026 villages (rural desa and urban kelurahan). The regencies (with their administrative capitals) and cities are enumerated below. East Kalimantan is one of the main gates to the eastern part of Indonesia. The area is also known as a storehouse of timber and mining, has hundreds of rivers (scattered across almost all regencies and cities) which area the main means of transportation in addition to land transport, with the longest river being the Mahakam.
East Kalimantan borders North Kalimantan in the north, South Kalimantan in the south, Central Kalimantan in the southwest, and West Kalimantan and Sarawak in the west. It touches the Celebes Sea and the Makassar Strait in the east, with its large Mangkalihat Peninsula separating the two. There are hills in almost all districts, and there are numerous lakes. Most lakes are located in the Kutai Regency, with the most extensive lakes, Semayang and Melintang, having an area of 13,000 ha and 11,000 ha respectively.
Climate
Such as the climate of Indonesia in general, East Kalimantan tropical climate and has two seasons, dry and rainy seasons. The dry season usually occurs in May to October, while the rainy season in November to April. This situation continued every year interspersed with transitional season in certain months. Moreover, because of its location on the equator, the climate in East Kalimantan are also affected by wind monsoon, monsoon wind is November–April west and east monsoon winds from May to October. In recent years, the situation in East Kalimantan season is sometimes erratic. In the months that it is supposed to rain, there is no rain at all, or vice versa in the months that should be dry it rains for a much longer time.
Temperature and humidity
Temperatures somewhere high and low are determined by the area of the ocean surface and the distance from the beach. In general, East Kalimantan hot climates with temperatures in 2013 ranged from 21.6 °C in Berau October to 35.6 °C in Berau in September. Aside from being a tropical area with extensive forests, in 2013 the average humidity between 83 and 87 percent of East Kalimantan. The lowest air humidity observed by the meteorological station Samarinda happens in a few months with 82 percent humidity. While the highest occurred in Berau in February with 91 percent humidity.
Rainfall and wind conditions
Rainfall in East Kalimantan region varies by month and location of monitoring stations. Average highest rainfall recorded at the Meteorological Station Berau amounted to 245.1 mm and the lowest for the year 2013 was recorded at the Meteorological Station Samarinda is 237.8 mm. At some monitoring stations monitor wind conditions in East Kalimantan in 2013. Observations show that wind speeds between 3 and 4 knots. The highest wind speed was 4 knots in Balikpapan and Berau, while the lowest was 3 knots in Samarinda.
Government and administrative divisions
thumb|East Kalimantan Governor Office
Administrative divisions
thumb|Map of regencies and cities
East Kalimantan consists of 7 regencies and 3 cities, in turn divided into 105 districts.
Ecology
thumb|right|upright=1.1|alt=Map of East Kalimantan showing tree-cover loss years, with forest remaining since 2000 in green and loss years shaded yellow through purple.|Tree-cover loss year in East Kalimantan, 2001-2024, from the [[Global Forest Change dataset.]]
thumb|left|Logging road in East Kalimantan: logged forest on the left, [[Old-growth forest|primary forest on the right]]
thumb|Melintan Lake in Kutai Kartanegara Regency
Illegal logging has removed much of the original forests of the province. Less than half the original forest remains in places such as the Kayan Mentarang and the Kutai national parks.
The projects that supports tropical rainforest conservation includes a WWF project and Samboja Lestari lodge, one of Borneo Orangutan Survival Foundation's reforestation and orangutan rehabilitation projects.
Economy
thumb|Economy of East Kalimantan is very dependent on [[Petroleum and Mining, especially in Coal.]]
East Kalimantan's economy heavily depends on earth resources such as oilfield exploration, natural gas, coal and gold. Balikpapan has an oil refinery plant that was built by Dutch governance before World War II, destroyed during World War II, and rebuilt after Indonesian independence.
Other developing economic sectors include agriculture and tourism.
Obstacles to economic development include a lack of transportation infrastructure. Transportation depends on traditional boats connecting coastal cities and areas along main river, Mahakam River.
In 2012, Russia's state railway firm Joint Stock Company (JSC) signed a memorandum of understanding with the East Kalimantan governor over railway lines to transport coal and other freight. The first stage will connect an area near Balikpapan port to West Kutai Regency in a 183-kilometer line and is estimated to cost about $1.8 billion. It will commence in 2013 and by 2017 it is hoped that it carry 20 million tons of coal annually. The second phase will connect a line to Murung Raya in Central Kalimantan with a 60 kilometer line, which will cost an estimated $600 million.
Several oil fields have been discovered in the Mahakam River Delta including Attaka, Badak (1971), Semberah, Nilam, Sanga Sanga, Bekapai (1972), Handil (1974), Samboja, Jakin and Sepinggan. The Handil, Badak and Bekapai fields are anticline structural traps with oil reservoir sandstones between 450 and 2900 m.