Thailand has a tropical, monsoonal climate. The heart of the country, the fertile and thickly populated central plain, is dotted with numerous rice paddies, entirely flat and rarely more than a few feet above sea level. It is watered by the Chao Phraya and lesser rivers and is elaborately veined by a system of canals (called klongs) for irrigation and drainage. Bangkok and Ayutthaya, the old capital, are in that basin.
The north is mountainous, with peaks rising to c.8,500 ft (2,590 m); mountains stretch south along the boundary with Myanmar on the west. Forests in the north yield teak, although overcutting has decreased Thailand's forest reserves severely. Although the population in the north is relatively sparse, rice is intensively cultivated in the river valleys, and one of the country's major cities, Chiang Mai, is in that area.
Most of NE and E Thailand is occupied by the Korat (Khorat) plateau, which is cut off from the rest of the country by highlands and the Phetchabun Mts. It is a hilly, dry, and generally poor region, where livestock raising is dominant. Chief towns are Nakhon Ratchasima (Korat), Udon Thani, and Ubon Ratchathani.
Peninsular Thailand in the south (which includes Phuket and other offshore islands) is largely mountainous and covered with jungles. It is the principal source of the rubber and tin that make Thailand a major world producer of both. Chief towns of the peninsula are Hat Yai and Songkhla, the second largest port of the country.
While 75% of the people are ethnically Thai, the country has a large Chinese minority, accounting for almost 15% of the population. Local trade is chiefly in the hands of the Chinese, and as a consequence there has been substantial tension between Thais and Chinese. Other sizable minorities include the Muslim Malays, concentrated in the southern peninsula; the hill tribes of the north; the Khmers, or Cambodians, who are found in the southeast and on the Cambodian border; and the Vietnamese, who live along the Mekong River. While the ethnic minorities generally speak their own languages, Thai (linguistically related to Chinese) is the official tongue; English predominates among the Western languages. Theravada Buddhism is the state religion; some 95% of the people are Buddhists, while about 5% are Muslims.