The mountains of the North
Northern Thailand has many high mountains cut by river valleys. This is where many of the country's rivers originate, including the Mekong, Chao Phraya and Salawin. At 2,565 metres, Doi Inthanon, located in the national park of the same name in Chiang Mai province, is the country's highest peak. Doi Suthep, with the famous Wat Phra That at its 1,050-metre peak, dominates the city of Chiang Mai, the country's largest urban area. With its tropical savannah climate, this region is ideal for various types of agriculture, particularly rice growing. The large rice terraces, particularly at Ban Pa Pong Piang, form magnificent landscapes that attract many travellers. The main towns are Chiang Mai, Chiang Rai, Mae Hong Son, Nakhon Sawan, Petchabun, Phitsanulok and Sukhothai.
The central plains
The heart of the country is irrigated by numerous rivers, notably the Chao Phraya, Mae Klong, Tha Jean, Pa Sak and Bang Pa Kong. The large plains that facilitate overland communications, together with the irrigation systems put in place during the Sukhothai kingdom, have enabled the agricultural and economic development of this region, often referred to as the "rice bowl of Asia". This fertile region is densely populated, more so than the rest of the country. The Chao Praya delta is the economic lung of the country; once the kingdom of Siam was centered on its capital Ayutthaya, today the capital of contemporary Thailand is Bangkok.
The main cities are Bangkok, Ayutthaya and Lopburi.
The North-East plateaus
Isaan, Thailand's largest province, covers the whole of this geographical region, which is bordered by the Mekong River to the north and east, and by Cambodia to the south. The Khorat plateau makes up most of this flat terrain, with a few rocky hills, the Phu Phan mountains. The soil is not very fertile and is covered with tall grasses. The Chi and Moon rivers meander through the plains. The long dry season is not conducive to agriculture, which is the main economic activity, especially as the monsoon is short and often floods. Only the cultivation of glutinous rice, the region's staple food, is favored by this climate and the flooding of the rivers. The main towns are Nakhon Ratchasima, Ubon Ratchathani and Udon Thani.
The western mountains
This narrow strip stretches across the Tenasserim chain along the border with Myanmar, from the Shan Hills in the north to Chumphon province in the south. The relief is made up of high mountains and deep river valleys, and a coastline stretching from the outskirts of Bangkok to the port of Chumphon. The region's largest city is the seaside resort of Hua Hin. The region's forests are largely untouched by human impact, and are protected by national parks such as Khao Sam Roi Yot (Prachuap Khiri Khan), home to the country's largest freshwater marshes. There are also some of the country's largest dams. The main industrial activity is mining. The main towns are Hua Hin, Kanchanaburi, Phetchaburi and Prachuap Khiri Khan.
Eastern Mountains and Coastal Plains
This border region with Cambodia is made up of high mountains and coastal plains to the north, river plains amid jagged sierra and rolling plains to the east, and coastline to the south. The Bang Pakong River crosses the region from north to south as far as the Gulf of Thailand. Between the Ban Tad and Chanthaburi mountains lies a narrow plain ideal for growing fruit. A UNESCO World Heritage site, the Dong Phayayen-Khao Yai forest complex stretches for 230 km between Ta Phraya National Park on the Cambodian border to the east, and Khao Yai National Park to the west. The coastline is covered with beautiful beaches, and offshore are the islands of Koh Chang, Koh Kood and Ko Samet. The Mu Ko Chang National Park is a protected marine area. Tourism plays a major role in the region's economy, thanks in particular to the islands, but also to the coastal resorts, especially Pattaya. The main cities are Pattaya, Chantaburi, Chonburi and Rayong.
Mountains, plateaus, coastal plains and southern islands
Southern Thailand lies on a narrow peninsula. Two coastal plains to the east and west are divided by high mountain ranges running through the center of the peninsula. The hilly, mountainous terrain and lack of major rivers are characteristic of this region. It is also a major tourist center, with numerous islands and seaside resorts. The landscapes formed by karst peaks emerging from the Andaman Sea are awe-inspiring. Among the best-known islands are Koh Samui and Koh Phangan to the west in the Gulf of Thailand, and Phuket, Koh Phi Phi, Koh Lanta and Koh Lipe to the east in the Andaman Sea. The peninsula's economy is based mainly on tourism, but also on palm oil and rubber plantations. The main towns are Nakhon Si Thammarat, Songkhla, Surat Thani, Narathiwat and Krabi.
Hydrography
Water is everywhere in Thailand, so the hydrographic network is highly developed and has played an essential role in the development of agriculture and transport. Numerous rivers, along which villages have sprung up, flow down from the northern mountains. The Ping and Nan rivers at Nakhon Sawan swell and merge to form the Chao Phraya, which then flows north-south for 372 kilometers from the central plains through Bangkok to the Gulf of Thailand. The Mekong, 4,880 kilometers long, descends from the Tibetan plateau, crossing China's Yunnan province, Myanmar, Thailand, Laos, Cambodia and Vietnam. These two rivers form Thailand's main river systems, providing irrigation, drinking water, transport, electricity and livelihoods for a large number of citizens, justifying why almost all of Thailand's major cities are located along rivers.
