Thailand ( /ˈtaɪlænd/ TY-land or /ˈtaɪlənd/ TY-lənd; Thai: ประเทศไทย, RTGS: Prathet Thai), officially the Kingdom of Thailand (Thai: ราชอาณาจักรไทย, RTGS: Ratcha Anachak Thai; ), formerly known as Siam (Thai: สยาม; RTGS: Sayam), is a country located at the centre of the Indochina peninsula in Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the west by the Andaman Sea and the southern extremity of Burma. Its maritime boundaries include Vietnam in the Gulf of Thailand to the southeast, and Indonesia and India in the Andaman Sea to the southwest.
The country is a constitutional monarchy, headed by King Rama IX, the ninth king of the House of Chakri, who, having reigned since 1946, is the world's longest-serving head of state and the longest-reigning monarch in Thai history. The king of Thailand is titled Head of State, Head of the Armed Forces, the Upholder of the Buddhist religion, and the Defender of all Faiths.
Thailand is the world's 51st-largest country in terms of total area, with an area of approximately 513,000 km2 (198,000 sq mi), and is the 20th-most-populous country, with around 64 million people. The capital and largest city is Bangkok, which is Thailand's political, commercial, industrial and cultural hub. About 75% of the population is ethnically Thai, 14% is of Chinese origin, and 3% is ethnically Malay; the rest belong to minority groups including Mons, Khmers and various hill tribes. The country's official language is Thai. The primary religion is Buddhism, which is practiced by around 95% of the population.
Thailand experienced rapid economic growth between 1985 and 1996, and is presently a newly industrialized country and a major exporter. Tourism also contributes significantly to the Thai economy. There are approximately 2.2 million legal and illegal migrants in Thailand, and the country has also attracted a number of expatriates from developed countries.