Thailand occupies the relatively low central section of the Indochinese peninsula, extending from N to S for approx. 1700 km, with a maximum width of approx. 800 km. The territory largely corresponds to a large depression area, invaded in the Cenozoic era by the waters of the Gulf of Siam and subsequently filled by recent river deposits, left by the Menam (Chao Praya) and its tributaries. Facing S to the sea, this plain – rich, well irrigated, very populated – is the main nucleus of the country, closed to the N by a series of meridian alignments, in several points with peaks of over 2000 m (Doi Luang, 2195 m; Doi Pha Homfok, 2298 m), which are tied, across the Shan plateau, in Myanmar, to the Chinese mountain bands of Yunnan. They continue towards the S forming a long chain on the border with Myanmar, practically interrupted only at the Three Pagodas pass (282 m) between the Dawna mountains to the N and the Bilauktaung mountains to S. The maximum height of these reliefs, which form the western edge of the Menam plain exceeds 2000 m in some points; are made up of limestone rocks of the Paleozoic era that have undergone a rejuvenation in the cenozoic. More modest heights, on the other hand, close the Menam plain to the E, forming the dividing line – not always clearly marked – along which the watershed with the Mekong basin runs., the mighty Indochinese river (4500 km) which largely marks the border between Thailand and Laos. However, these rises separate, in northeastern Thailand, the so-called Khore plateau, in reality a succession of modest undulations and lowlands mostly between 100 and 200 m in height. Finally, the southern end of Thailand, which includes the stretch of the Malay peninsula to the S of the Khwae Noi valley up to the border with Malaysia, faces the Gulf of Siam on the E and the Andaman Sea on the W. Beyond the Isthmus of Kra (42 km, no more than 76 m high and entirely in Thai territory) the relief includes a series of isolated granite massifs (Khao Lang Kha Toek, 1465 m), alternating with depressions, whose origin is connected to the formation of faults that have the peninsula was broken up and fragmented. The coasts facing the Gulf of Siam (1875 km) are mainly low and bordered by lagoons. There are numerous islands that emerge from the continental shelf: the largest are Chang and Kut, near the east coast, and Samui and Phangan, off the west coast. The coast overlooking the Andaman Sea is instead rocky, jagged and full of rocks, islets and islands, the largest of which is that of Phuket with 522 km² of surface.
The most important river in Thailand is the Menam, which forms just upstream of Nakhon Sawan from the confluence of the Ping and Nan rivers, coming respectively from the mountains on the border with Myanmar and Laos. Soon the river branches out into numerous branches that lazily cross a leveled plain: the two main branches are the Suphan Buri, to the W, and the Chao Phraya, or Menam proper. The abundant floods poured into the Gulf of Siam they tend to fill the latter; the tides are however able to keep the various delta arms clear, which are navigable. The Menam regime is closely connected with the monsoon rains: the river begins to swell in May and reaches its highest level in October. For the rest, apart from a narrow area to the NW tributary of Salween, and the peninsular portion, in which modest streams flow directly into the sea, the Thai territory is tributary of the Mekong, mainly through the Menam Mun; however, the drainage of the Khorat is complicated by the presence of low-pressure areas occupied by lakes. Check sportsqna to see Tips for the First Time in Thailand.
About 37% of the Thai territory is still covered by woods and forests; the rainforest, rich in precious essences, appears where rainfall is most abundant, covering the best sprayed reliefs, such as the mountains of the Malacca peninsula, especially the side facing Myanmar, and, in part, the western edge of the Khorat plateau. Where the monsoon regime is more pronounced and the seasons are clearly differentiated, a less dense forest prevails: almost the entire northern section of Thailand, with rainfall between 1200 and 2000 mm per year, is covered by the so-called high forest (which, moreover, has been largely degraded by the practice of itinerant agriculture, still widespread, and by irrational deforestation), whose best known species is teak; in the less rainy areas or with poor soils, as in Khorat, the arid forest dominates, without undergrowth, with lower and sparse trees. The plains have been considerably transformed by human intervention: rice fields have replaced the savannah expanses and bands of arboreal vegetation persist only along the waterways. Mangrove formations are highly developed along the stretches of low and muddy coasts. Thanks to the dense vegetation, Thailand boasts a rich and diverse fauna. Elephants, traditionally used as pack animals, are bred in captivity, but are also found in the wild. Other large native animals include rhinos, tigers, leopards, Asian brown bears, and crocodiles. There are also more than 50 snake species in the country, including the most venomous varieties, 850 bird species and a rich fish population. However, many animals are at risk from widespread poaching, while some species, such as the Schomburgk deer, have already become extinct. To defend the natural heritage, since the end of the 1960s, the government has promoted an environmental policy, with the creation of protected areas that cover an area equal to 16.4 of the country. Currently there are 81 national parks and 21 national marine parks, as well as numerous wildlife oases and areas with no hunting. Two protected areas have been declared UNESCO heritage: the Thungyai-Huai Kha Khaeng wildlife sanctuary (1991) and the Dong Phayayen-Khao Yai forest complex (2005).