Geographic coordinates
By the 12th century, a number of loosely connected rice-growing and trading states flourished in the upper Chao Phraya Valley. Starting in the middle of the 14th century, these central chiefdoms gradually came under the control of the Ayutthaya kingdom at the southern extremity of the floodplain.
Successive capitals, built at various points along the river, became centers of great Thai kingdoms based on rice cultivation and foreign commerce. Unlike the neighboring Khmer and Burmese, the Thai continued to look outward across the Gulf of Thailand and the Andaman Sea toward foreign ports of trade.
When European imperialism brought a new phase in Southeast Asian commerce in the late 1800s, Thailand (known then as Siam) was able to maintain its independence as a buffer zone between British-controlled Burma to the west and French-dominated Indochina to the east, but losing over 50% of its territory in the process.
 Land boundaries
- Total: 3,219 km
 Maritime claims
- territorial sea: 12 nmi (22.2 km; 13.8 mi)
- exclusive economic zone: 200 nmi (370.4 km; 230.2 mi)
- continental shelf: 200-m depth or to the depth of exploitation
 Topography and drainagehigh mountains, a central plain, and an upland plateau. Mountains cover much of northern Thailand and extend along the Myanmar border down through the Kra Isthmus and the Malay Peninsula. The central plain is a lowland area drained by the Chao Phraya River and its tributaries, the country's principal river system, which feeds into the delta at the head of the Bay of Bangkok. The Chao Phraya system drains about one-third of the nation's territory. In the northeastern part of the country the Khorat Plateau, a region of gently rolling low hills and shallow lakes, drains into the Mekong through the Mun River. The Mekong system empties into the South China Sea and includes a series of canals and dams.
Together, the Chao Phraya and Mekong systems sustain Thailand's agricultural economy by supporting wet-rice cultivation and providing waterways for the transport of goods and people. In contrast, the distinguishing natural features of peninsular Thailand are long coastlines, offshore islands, and diminishing mangrove swamps.
- Total: 514 000 km²
- Land: 511 770 km²
- Water: 2 230 km²
 Extreme points
- Northernmost point: Myanmar border, Mae Sai District, Chiang Rai Province, at
- Southernmost point: Malaysian border, Betong District, Yala Province, at
- Easternmost point: Laos border, Khong Chiam District, Ubon Ratchathani Province, at
- Westernmost point: Myanmar border, Mae Sariang District, Mae Hong Son Province, at
 Elevation extremes
 Northern ThailandDuring the winter months in mountainous Northern Thailand, the temperature is cool enough for the cultivation of fruits such as lychees and strawberries. These high mountains are incised by steep river valleys and upland areas that border the central plain. A series of rivers, including the Nan, Ping, Wang, and Yom, unite in the lowlands to form the Chao Phraya Watershed. Traditionally, these natural features made possible several different types of agriculture, including wet-rice farming in the valleys and shifting cultivation in the uplands. The forested mountains also promoted a spirit of regional independence. Forests, including stands of teak and other economically useful hardwoods that once dominated the North and parts of the Northeast, had diminished by the 1980s to 130,000 km². In 1961 they covered 56 % of the country, but by the mid-1980s forestland had been reduced to less than 30 % of Thailand's total area.
 Northeastern ThailandThe Northeast, with its poor soils, is not favoured agriculturally. However, sticky rice, the staple food of the region, which requires flooded, poorly drained paddy fields, thrives and where fields can be flooded from nearby streams, rivers and ponds, often two harvests are possible each year. Cash crops such as sugar cane and manioc are cultivated on a vast scale, and to a lesser extent, rubber. Silk production is an important cottage industry and contributes significantly to the economy.
The region consists mainly of the dry Khorat Plateau which in some parts is extremely flat, and a few low but rugged and rocky hills. The short monsoon season brings heavy flooding in the river valleys. Unlike the more fertile areas of Thailand, the Northeast has a long dry season, and much of the land is covered by sparse grasses. Mountains ring the plateau on the west and the south, and the Mekong delineates much of the northern and eastern rim. Some varieties of traditional medicinal herbs, particularly of the Genus Curcuma, family Zingiberaceae, are indigenous to the region.
 Central ThailandThe "heartland", Central Thailand, is a natural self-contained basin often termed "the rice bowl of Asia." The complex irrigation system developed for wet-rice agriculture in this region provided the necessary economic support to sustain the development of the Thai state from the 13th century Sukhothai kingdom to contemporary Bangkok. Here the rather flat unchanging landscape facilitated inland water and road transport. The fertile area was able to sustain a dense population, 422 persons per square kilometer in 1987, compared with an average of 98 for the country as a whole. The terrain of the region is dominated by the Chao Phraya and its tributaries and by the cultivated paddy fields. Metropolitan Bangkok, the focal point of trade, transport, and industrial activity, is situated on the southern edge of the region at the head of the Gulf of Thailand and includes part of the delta of the Chao Phraya BTS
 Eastern ThailandEastern Thailand lies between the Sankambeng Range, which forms the border of the Northeastern plateau to the north and the Gulf of Thailand to the south. The geography of the region is characterised by short mountain ranges alternating with small basins of short rivers which drain into the Gulf of Thailand.
Fruit is a major component of agriculture in the area, and tourism plays a strong part in the economy. The region's coastal location has helped promote the Eastern Seaboard industrial development, a major factor in the economy of the region.
 Western ThailandThailand's long mountainous border with Myanmar continues south from the North into Western Thailand with the Tenasserim Hills. The geography of the western region of Thailand, like the North, is characterised by high mountains and steep river valleys.
Western Thailand hosts much of Thailand's less-disturbed forest areas. Water and minerals are also important natural resources; the region is home to many of the country's major dams, and mining is an important industry in the area.
 Southern ThailandSouthern Thailand, part of a narrow peninsula, is distinctive in climate, terrain, and resources. Its economy is based on rice cultivation for subsistence and rubber production for industry. Other sources of income include coconut plantations, tin mining, and tourism, which is particularly lucrative on Phuket Island. Rolling and mountainous terrain and the absence of large rivers are conspicuous features of the South. North-south mountain barriers and impenetrable tropical forest caused the early isolation and separate political development of this region. International access through the Andaman Sea and the Gulf of Thailand made the South a crossroads for both Theravada Buddhism, centered at Nakhon Si Thammarat, and Islam, especially in the former Pattani kingdom on the border with Malaysia.
 ProvincesThailand's regions are further politically divided into a total of 75 provinces,such as Ratchaburi,Petchaburi etc. plus Bangkok, which is a special administrative area. The country's provinces have the same names as their respective capitals.
 ClimateKöppen climate classification, while the South and the eastern tip of the East have a tropical monsoon climate (Am); countrywide, temperatures normally range from an average annual high of 38 °C (100.4 °F) to a low of 19 °C (66.2 °F). During the dry season, the temperature rises dramatically in the second half of March, spiking to well over 40 °C (104 °F) in some areas by mid April when the Sun passes the Zenith. Southwest monsoons that arrive between May and July (except in the South) signal the advent of the rainy season (ruedu fon), which lasts into October and the cloud covering reduces the temperature again but the high humidity is experienced as 'hot and sticky'. November and December mark the onset of the dry season and night temperatures on high ground can occasionally drop to a light frost. Temperatures begin to climb in January, and a hot sun parches the landscape. The dry season is shortest in the South because of the proximity of the sea to all parts of the Malay Peninsula. With only minor exceptions, every area of the country receives adequate rainfall, but the duration of the rainy season and the amount of rain vary substantially from region to region and with altitude. The Northeast experiences a long dry season although the dry 2007/2008 season lasted only from late November through mid March. Its red,(laterite) dense clayey soils retain water well, which limits their agricultural potential for many crops but is ideal for keeping the water in the paddy fields and local village reservoirs. The well drained, loose sandy alluvium of the Mekong flood plain is very fertile, the main crops being tomatoes on an industrial scale, tobacco, and pineapples.
 Resources and land use
 Natural resources
- Tin, rubber, natural gas, tungsten, tantalum, timber, lead, fish, gypsum, lignite, fluorite, arable land.
 Land use
- Arable land: 34%
- Permanent crops: 6%
- Permanent pastures: 2%
- Forests and woodland: 26%
- Other: 32% (1993 est.)
 Irrigated land
- Total: 44,000 km² (1993 est.)
 Environmental concerns
 Natural hazardsLand subsidence in Bangkok area resulting from the depletion of the water table; droughts (see also 2004 Indian Ocean earthquake).
 Current environmental issues
- Air pollution from vehicle emissions
- Water pollution from organic and factory wastes
- Forest fires
- Soil erosion
- Wildlife populations threatened by illegal hunting
 International environmental agreements
- Party to: Climate Change, Endangered Species, Hazardous Wastes, Marine Life Conservation, Nuclear Test Ban, Ozone layer protection, Tropical Timber 83, Tropical Timber 94, Wetlands
- Signed, but not ratified: Biodiversity, Climate Change (Kyoto Protocol), Law of the Sea
 Territorial disputes
 HistoryThailand shares boundaries with Cambodia, Laos, Malaysia and Myanmar. Although neither China nor Vietnam border Thailand, the territories of both countries come within 100 km of Thai territory.
Many parts of Thailand's boundaries followed natural features, such as the Mekong. Most borders had been stabilized and demarcated in the late 19th and early 20th centuries in accordance with treaties forced on Thailand and its neighbors by Britain and France. In some areas, however, exact boundaries, especially along Thailand's eastern borders with Laos and Cambodia, are still in dispute.
Adding to general border tensions were the activities of communist-led insurgents, whose operations had been of paramount concern to the Thai government and its security forces for several decades. The problem of communist insurgency was compounded by the activity of what the Thai government labeled "antistate elements." Often the real source of border problems was ordinary criminals or local merchants involved in illegal mining, logging, smuggling, and narcotics production and trade.