With an area of 513,115sqkm (198,404sqmi), Thailand has roughly the size of France. Located between 6° and 21° north latitude and 97° and 106° east longitude, she is bordered in the north by Burma and Laos, in the west by Burma, in the east by Cambodia and Laos and in the south by Malaysia (and the Gulf of Thailand). The longest north-south distance is about 1500km (930mi), the longest east-west distance about 800km (500mi).

The topography is flat alluvial plains intersected by winding rivers and streams in central Thailand, a plateau in the northeast, forest-covered mountains and hills in the north and mostly hills in the south.

Central Thailand - The central region is considered the heartland of the country. Basically it encompasses the alluvial plains created by the Chao Phaya River. The region is the most fertile of the country, and due to an extensive network of canals and small irrigation projects, the area is a major producer of rice. It is also the most densely populated region of the country, with the capital, Bangkok, in its midst.

Northern Thailand - This region is composed of a series of parallel mountain ranges with an average elevation of 1,200m (3,900ft) above sea level, incised by steep valleys of the Ping, Wang, Yom, and Nan rivers. A large part of these mountains is still covered with tropical monsoon forests, though the most valuable timber, teak, has been cut to a wide extent (the government has now imposed a full logging ban). Doi Inthanon, with an elevation of 2,595m (8,514ft) the highest point in the country, is located in the extreme northwest of the region. The first three Thai kingdoms in Indochina had their capitals in northern Thailand, at Sukhothai, Chiang Mai and Chiang Saen. The second largest city of present-day Thailand, Chiang Mai, is the center of the northern region. The northernmost corner of northern Thailand belongs to the region dubbed Golden Triangle - one of the world's major producers of opium.

Northeastern Thailand - The region principally consists of a saucer shaped plateau known as Khorat Plateau with an average elevations of 200m (650ft). The region's soils are poor and sandy and rainfall is scant except for the rainy season from June to October when much of the land is flooded. Areas not used for agriculture are largely covered with savanna-type grasses and shrubs. The Northeast is the least developed region of the country, and the least favored by tourists.

East Coast - This part of the country, geographically the southern edge of northeastern Thailand along the Gulf of Thailand, has not traditionally been considered a separate region of the country. The division, often made today, is based on administrative and social factors more than on geological features. The region is distinguished from the Northeast in that it is far richer - the second richest region of the country, after the central plain. The East Coast has a well-established industrial and touristic infrastructure. Furthermore contributing to the region's wealth are extraordinary fruits (durians and mangos) as well as extraordinary stones (rubies and sapphires).

Southern Thailand - Occupying the northern half of the Malay Peninsula, the region has a rolling to mountainous topography with little flat land. The countryside is often breath-taking, and this asset is increasingly tapped for the development of tourism. Traditionally, the region's relative wealth stems from its most important natural resources, tin and rubber.