Bangkok covers an area of , ranking 69th among the other 76 provinces of Thailand. Of this, about forms the built-up urban area. The city's
urban sprawl reaches into parts of the six other provinces that it borders, namely, in clockwise order from northwest:
Nonthaburi,
Pathum Thani,
Chachoengsao,
Samut Prakan,
Samut Sakhon, and
Nakhon Pathom. Except for Chachoengsao, these provinces, together with Bangkok, form the greater
Bangkok Metropolitan Region.
Topography Bangkok is situated in the Chao Phraya River delta in Thailand's
central plain. The river meanders through the city in a southerly direction, emptying into the
Gulf of Thailand approximately south of the city centre. The area is flat and low-lying, with an average elevation of
above sea level. Most of the area was originally
swampland, which was gradually drained and irrigated for agriculture by the construction of canals (
khlong) which took place from the 16th to 19th centuries. The course of the river as it flows through Bangkok has been modified by the construction of
several shortcut canals. The city's waterway network served as the primary means of transport until the late 19th century, when modern roads began to be built. Up until then, most people lived near or on the water, leading the city to be known during the 19th century as the "
Venice of the East". Many of these canals have since been filled in or paved over, but others still crisscross the city, serving as major drainage channels and transport routes. Most canals are now badly polluted, although the BMA has committed to the treatment and cleaning up of several canals. The geology of the Bangkok area is characterised by a top layer of soft
marine clay, known as "Bangkok clay", averaging in thickness, which overlies an
aquifer system consisting of eight known units. This feature has contributed to the effects of
subsidence caused by extensive groundwater pumping. First discovered in the 1970s, subsidence soon became a critical issue, reaching a rate of per year in 1981. Ground water management and mitigation measures have since lessened the severity of the situation, and the rate of subsidence decreased to per year in the early 2000s, though parts of the city are now below sea level. Subsidence has resulted in increased flood risk, as Bangkok is already prone to flooding due to its low elevation and an inadequate drainage infrastructure, often compounded by blockage from rubbish pollution (especially plastic waste). The city now relies on flood barriers and augmenting drainage from canals by pumping and building drain tunnels, but parts of Bangkok and its suburbs are still regularly inundated. Heavy downpours resulting in
urban runoff overwhelming drainage systems, and runoff discharge from upstream areas, are major triggering factors. Severe flooding affecting much of the city occurred in 1995 and
2011. In 2011, most of Bangkok's northern, eastern, and western districts were flooded, in some places for over two months. Bangkok's geology also makes its tall buildings vulnerable to powerful earthquakes from far away, despite not being in a seismically active area, as the clay layer has an amplifying effect on
long-period ground motion, which tends to match the
resonant frequency of high-rises. Occupants of skyscrapers in Bangkok have often felt effects from earthquakes centred hundreds of kilometres away in
northern Thailand and Myanmar. Seismic considerations were only added to the building code in 2007, making older structures particularly at risk. . Its coastal location makes Bangkok particularly vulnerable to
rising sea levels due to
global warming and climate change. A study by the
OECD has estimated that 5.138 million people in Bangkok may be exposed to
coastal flooding by 2070, the seventh highest figure among the world's port cities. There are fears that the city may be submerged by 2030. A study published in October 2019 in
Nature Communications corrected earlier models of coastal elevations and concluded that up to 12 million Thais—mostly in the greater Bangkok metropolitan area—face the prospect of annual flooding events. This is compounded by coastal erosion, which is an issue in the gulf coastal area, a small length of which lies within Bangkok's
Bang Khun Thian District. Tidal flat ecosystems existed on the coast; however, many have been reclaimed for agriculture, aquaculture, and salt works. The closest mountain range to Bangkok is the
Khao Khiao Massif, about southeast of the city. Phu Khao Thong, the only hill in the metropolitan area, originated with a very large
chedi that King
Rama III (1787–1851) built at
Wat Saket. The chedi collapsed during construction because the soft soil could not support its weight. Over the next few decades, the abandoned mud-and-brick structure acquired the shape of a natural hill and became overgrown with weeds. The locals called it
phu khao (), as if it were a natural feature. In the 1940s, enclosing concrete walls were added to stop the hill from eroding.
Climate Like most of Thailand, Bangkok has a
tropical savanna climate (Aw) under the
Köppen climate classification and is under the influence of the
Asian monsoon system. The city experiences three seasons: hot, rainy, and cool, although temperatures are fairly hot year-round, ranging from an average low of in December to an average high of in April. The annual average temperature is . The rainy season begins with the arrival of the southwest
monsoon around mid-May. September is the wettest month, with an average rainfall of . The rainy season lasts until October, when the dry and cool northeast monsoon takes over until February. The hot season is generally dry, but it also sees occasional summer storms. The surface magnitude of Bangkok's
urban heat island has been measured at during the day and at night. The highest recorded temperature of Bangkok metropolis was on 7 May 2023, and the lowest recorded temperature was in January 1955. The Climate Impact Group at
NASA's
Goddard Institute for Space Studies projected severe weather impacts on Bangkok caused by
climate change. It found that Bangkok in 1960 had 193 days at or above 32 °C. In 2018, Bangkok can expect 276 days at or above 32 °C. The group forecasts a rise by 2100 to, on average, 297 to 344 days at or above 32 °C. Thai Meteorological Department (Feb–May record highs, 1951–2022; Nov–Feb record lows, 1951–2021 }}
Districts )
Bangkok's fifty districts serve as administrative subdivisions under the authority of the BMA. Thirty-five of these districts lie to the east of the Chao Phraya, while fifteen are on the western bank, known as the Thonburi side of the city. The fifty districts, arranged by district code, are: •
Phra Nakhon district •
Dusit district •
Nong Chok district •
Bang Rak district •
Bang Khen district •
Bang Kapi district •
Pathum Wan district •
Pom Prap Sattru Phai district •
Phra Khanong district •
Min Buri district •
Lat Krabang district •
Yan Nawa district •
Samphanthawong district •
Phaya Thai district •
Thon Buri district •
Bangkok Yai district •
Huai Khwang district •
Khlong San district •
Taling Chan district •
Bangkok Noi district •
Bang Khun Thian district •
Phasi Charoen district •
Nong Khaem district •
Rat Burana district •
Bang Phlat district •
Din Daeng district •
Bueng Kum district •
Sathon district •
Bang Sue district •
Chatuchak district •
Bang Kho Laem district •
Prawet district •
Khlong Toei district •
Suan Luang district •
Chom Thong district •
Don Mueang district •
Ratchathewi district •
Lat Phrao district •
Watthana district •
Bang Khae district •
Lak Si district •
Sai Mai district •
Khan Na Yao district •
Saphan Sung district •
Wang Thonglang district •
Khlong Sam Wa district •
Bang Na district •
Thawi Watthana district •
Thung Khru district •
Bang Bon district Cityscape looking south from Bang Rak, 2017 Bangkok's districts often do not accurately represent the functional divisions of its neighbourhoods or land usage. Although
urban planning policies date back to the commission of the Litchfield Plan in 1960, which set out strategies for land use, transportation, and general infrastructure improvements, zoning regulations were not fully implemented until 1992. As a result, the city grew organically throughout its rapid expansion, both horizontally as
ribbon developments extended along newly built roads, and vertically, with increasing numbers of high rises and skyscrapers being built in commercial areas. The city has grown from its original centre along the river into a sprawling metropolis surrounded by swaths of suburban residential development extending north and south into neighbouring provinces. The highly populated and growing cities of
Nonthaburi,
Pak Kret,
Rangsit, and
Samut Prakan are effectively now suburbs of Bangkok. Nevertheless, large agricultural areas remain within the city proper at its eastern and western fringes, and a small amount of forest area is found within the city limits: , amounting to 0.4 per cent of the city area. Land use in the city consists of 23 percent residential use, 24 percent agriculture, and 30 percent used for commerce, industry, and government. in Dusit District was inspired by King Chulalongkorn's visits to Europe. Bangkok's historic centre remains the
Rattanakosin Island in Phra Nakhon District. It is the site of the
Grand Palace and the City Pillar Shrine, primary symbols of the city's founding, as well as important Buddhist temples. Phra Nakhon, along with the neighbouring Pom Prap Sattru Phai and Samphanthawong Districts, formed what was the city proper in the late 19th century. Many traditional neighbourhoods and markets are found here, including the Chinese settlement of
Sampheng. The
Victory Monument in Ratchathewi District is among its most important road junctions, serving over 100 bus lines as well as an elevated train station. From the monument,
Phahonyothin and
Ratchawithi / Din Daeng Roads respectively run north and east, linking to major residential areas. Most of the high-density development areas are within the area encircled by the
Ratchadaphisek inner ring road. Ratchadaphisek is lined with businesses and retail outlets, and office buildings also cluster around Ratchayothin Intersection in Chatuchak District to the north. Further from the city centre, most areas are primarily mid- or low-density residential. The Thonburi side of the city is less developed, with fewer high rises. Except for a few secondary urban centres, Thonburi, in the same manner as the outlying eastern districts, consists mostly of residential and rural areas. While most of Bangkok's streets are fronted by vernacular
shophouses, the largely unrestricted building euphoria of the 1980s has transformed the city into an urban area of skyscrapers and high rises of contrasting and clashing styles. There are 581
skyscrapers over tall in the city. Bangkok was ranked as the world's eighth-tallest city in 2016. As a result of persistent
economic disparity, many slums have emerged in the city. In 2000, over one million people were living in about 800
informal settlements. Some settlements are
squatted such as the large slums in
Khlong Toei District. In total, there were 125 squatted areas. compared to an average of in other cities across Asia. Bangkokians thus have 10 times less green space than is standard in the region's urban areas.
Green belt areas include about of rice paddies and orchards on the eastern and western edges of the city, although their primary purpose is to serve as flood
detention basins rather than to limit urban expansion.
Bang Kachao, a conservation area on an oxbow of the Chao Phraya, lies just across the southern riverbank districts, in
Samut Prakan province. A master development plan has been proposed to increase the total park area to per person. One of Bangkok's largest parks is the centrally located
Lumphini Park near the Silom–Sathon business district with an area of . It is connected by a 1.3 km elevated pedestrian and bicycle walkway to the Benjakitti Park, which includes a recently completed expansion including wetlands, skywalks, and rare plants. Other parks include the
Suanluang Rama IX in the east of the city, and the
Chatuchak–
Queen Sirikit–
Wachirabenchathat park complex in northern Bangkok, which has a combined area of . More parks are expected to be created through the Green Bangkok 2030 project, which aims to leave the city with of green space per person, including 30% of the city having tree cover. ==Demography==