Bangkok, known in Thai as Krung Thep Maha Nakhon and colloquially as Krung Thep, is the capital and most populous city of Thailand. The city occupies 1,568.7 square kilometres (605.7 sq mi) in the Chao Phraya River delta in central Thailand and has an estimated population of 9.1 million people as of 2024, 15.9% of the country's population. Over 17.4 million people (25% of Thailand's population) live within the surrounding Bangkok Metropolitan Region as of the 2021 estimate, making Bangkok a megacity and an extreme primate city, dwarfing Thailand's other urban centres in both size and importance to the national economy.
Bangkok traces its roots to a small trading post during the Ayutthaya era in the 15th century, which eventually grew and became the site of two capital cities, Thonburi in 1767 and Rattanakosin in 1782. Bangkok was at the heart of the modernization of Siam during the late 19th century, as the country faced pressures from the West. The city was at the centre of the country's political struggles throughout the 20th century, as Siam—later renamed Thailand—abolished absolute monarchy, adopted constitutional rule, and underwent numerous coups and several uprisings. The city, incorporated as a special administrative area under the Bangkok Metropolitan Administration in 1972, grew rapidly during the 1960s through the 1980s and now exerts a significant impact on Thailand's politics, economy, education, media, and modern society.
The Asian investment boom in the 1980s and 1990s led many multinational corporations to locate their regional headquarters in Bangkok. The city is now a regional force in finance, business, and pop culture. It is an international hub for transport and health care, and has emerged as a centre for the arts, fashion, and entertainment. The city is known for its street life and cultural landmarks, as well as its red-light districts. The Grand Palace and Buddhist temples, including Wat Arun and Wat Pho, stand in contrast with other tourist attractions such as the nightlife scenes of Khaosan Road and Patpong. Bangkok is among the world's top tourist destinations and has been named the world's most visited city in several international rankings.
Bangkok's rapid growth, coupled with little urban planning, has resulted in a haphazard cityscape and inadequate infrastructure. Despite an extensive expressway network, an inadequate road network and substantial private car usage have led to chronic and crippling traffic congestion, which caused severe air pollution in the 1990s. The city has since turned to public transport to solve the problem, operating 10 urban rail lines and building other public transit; however, congestion remains a prevalent issue.
The history of Bangkok dates at least back to the early 15th century, to when it was a village on the west bank of the Chao Phraya River, under the rule of Ayutthaya. Because of its strategic location near the mouth of the river, the town gradually increased in importance. Bangkok initially served as a customs outpost with forts on both sides of the river, and was the site of a siege in 1688, in which the French were expelled from Siam. After the fall of Ayutthaya to the Burmese in 1767, the newly crowned King Taksin established his capital at the town, which became the base of the Thonburi Kingdom. In 1782, King Phutthayotfa Chulalok (Rama I) succeeded Taksin, moved the capital to the eastern bank's Rattanakosin Island, thus founding the Rattanakosin Kingdom. The City Pillar was erected on 21 April 1782, which is regarded as the date of the foundation of Bangkok as the capital.
Bangkok's economy gradually expanded through international trade, first with China, then with Western merchants returning in the early to mid-19th century. As the capital, Bangkok was the centre of Siam's modernization as it faced pressure from Western powers in the late 19th century. The reigns of Kings Mongkut (Rama IV, r. 1851–68) and Chulalongkorn (Rama V, r. 1868–1910) saw the introduction of the steam engine, printing press, rail transport and utilities infrastructure in the city, as well as formal education and healthcare. Bangkok became the centre stage for power struggles between the military and political elite as the country abolished absolute monarchy in 1932.
As Thailand allied with Japan in World War II, Bangkok was subjected to Allied bombing, but rapidly grew in the post-war period as a result of US aid and government-sponsored investment. Bangkok's role as a US military R&R destination boosted its tourism industry, as well as firmly establishing it as a sex tourism destination. Disproportionate urban development led to increasing income inequalities and migration from rural areas into Bangkok; its population surged from 1.8 million to 3 million in the 1960s.
Following the US withdrawal from Vietnam in 1973, Japanese businesses took over as leaders in investment, and the expansion of export-oriented manufacturing led to the growth of the financial market in Bangkok. Rapid growth of the city continued through the 1980s and early 1990s, until it was stalled by the 1997 Asian financial crisis. By then, many public and social issues had emerged, among them the strain on infrastructure reflected in the city's notorious traffic jams. Bangkok's role as the nation's political stage continues to be seen in strings of popular protests, from the student uprisings in 1973 and 1976, anti-military demonstrations in 1992, and frequent street protests since 2006, including those by groups opposing and supporting former prime minister Thaksin Shinawatra from 2006 to 2013, and a renewed student-led movement in 2020.
Administration of the city was first formalized by King Chulalongkorn in 1906, with the establishment of Monthon Krung Thep Phra Maha Nakhon (มณฑลกรุงเทพพระมหานคร) as a national subdivision. In 1915, the monthon was split into several provinces, the administrative boundaries of which have since further changed. The city in its current form was created in 1972 with the formation of the Bangkok Metropolitan Administration (BMA), following the merger of Phra Nakhon province on the eastern bank of the Chao Phraya and Thonburi province on the west during the previous year.
The origin of the name Bangkok (บางกอก, pronounced in Thai as [bāːŋkɔ̀ːk] ) is unclear. Bang บาง is a Thai word meaning 'a village on a stream', and the name might have been derived from Bang Ko (บางเกาะ), ko เกาะ meaning 'island', stemming from the city's watery landscape. Another theory suggests that it is shortened from Bang Makok (บางมะกอก), makok มะกอก being the name of Elaeocarpus hygrophilus, a plant bearing olive-like fruit. This is supported by the former name of Wat Arun, a historic temple in the area, that used to be called Wat Makok.
Officially, the town was known as Thonburi Si Mahasamut (ธนบุรีศรีมหาสมุทร, from Pali and Sanskrit, literally 'city of treasures gracing the ocean') or Thonburi, according to the Ayutthaya Chronicles. Bangkok was likely a colloquial name, albeit one widely adopted by foreign visitors, who continued to use it to refer to the city even after the new capital's establishment.
When King Rama I established his new capital on the river's eastern bank, the city inherited Ayutthaya's ceremonial name, of which there were many variants, including Krung Thep Thawarawadi Si Ayutthaya (กรุงเทพทวารวดีศรีอยุธยา) and Krung Thep Maha Nakhon Si Ayutthaya (กรุงเทพมหานครศรีอยุธยา). Edmund Roberts, visiting the city as envoy of the United States in 1833, noted that the city, since becoming capital, was known as Sia-Yut'hia, and this is the name used in international treaties of the period.
The city's ceremonial name came into use during the reign of King Mongkut. The full name reads as follows:
Krungthepmahanakhon Amonrattanakosin Mahintharayutthaya Mahadilokphop Noppharatratchathaniburirom Udomratchaniwetmahasathan Amonphimanawatansathit Sakkathattiyawitsanukamprasitกรุงเทพมหานคร อมรรัตนโกสินทร์ มหินทรายุธยา มหาดิลกภพ นพรัตนราชธานีบูรีรมย์ อุดมราชนิเวศน์มหาสถาน อมรพิมานอวตารสถิต สักกะทัตติยวิษณุกรรมประสิทธิ์