Iran, officially Islamic Republic of Iran, with the population of over 82 million people and total area of 636,290 square meter (1,648,000 sq km) is located in south-west Asia. The country’s name was changed from Persia to Iran in 1935. Iran is bordered on the north by Armenia, Azerbaijan, Turkmenistan, and the Caspian Sea; on the east by Afghanistan and Pakistan; on the south by the Persian Gulf and the Gulf of Oman; and on the west by Turkey and Iraq. The Shatt al Arab forms part of the Iran-Iraq border. Tehran is the capital, largest city and the political, cultural, commercial, and industrial center of the nation.
Iran lies within the Alpine-Himalayan mountain system and is composed of a vast central plateau rimmed by mountain ranges and limited lowland regions. Iran is subject to numerous and often severe earthquakes and volcanic eruptions. The Iranian Plateau (alt. c.4,000 ft/1,200 m), which extends beyond the low ranges of E Iran into Afghanistan, is a region of interior drainage. It consists of a number of arid basins of salt and sand, such as those of Dasht-e Kavir and Dasht-e Loot, and some marshlands, such as the area around Hamun-i-Helmand along the Afghanistan border. The plateau is surrounded by high folded and volcanic mountain chains including the Kopet Mts. in the northwest, the Alborz Mts. (rising to 18,934 ft/5,771 m at Mt. Damavand, Iran’s highest point) in the north, and the complex Zagros Mts. in the west. Lake Urmia, the country’s largest inland body of water, is in the Zagros of NW Iran. Narrow coastal plains are found along the shores of the Persian Gulf, Gulf of Oman, and the Caspian Sea; at the head of the Persian Gulf is the Iranian section of the Mesopotamian lowlands. Of the few perennial rivers in Iran, only the Karun in the west is navigable for large craft; other major rivers are the Karkheh and the Sefid Rud.
The climate of Iran is continental, with hot summers and cold, rainy winters; the mountain regions of the north and west have a subtropical climate. Temperature and precipitation vary with elevation, as winds bring heavy moisture from the Persian Gulf. The Caspian region receives over 40 in. (102 cm) of rain annually. Precipitation occurs mainly in the winter and decreases from northwest to southeast. Much of the precipitation in the mountains is in the form of snow, and meltwater is vital for Iran’s water supply. The central portion of the plateau and the southern coastal plain (Makran) receive less than 5 in. (12.7 cm) of rain annually.
Iran’s central position has made it a crossroads of migration; the population is not homogeneous, although it has a Persian core that includes over half of the people. Azerbaijanis constitute almost a quarter of the population. The migrant ethnic groups of the mountains and highlands, including the Kurds, Lurs, Qashqai, and Bakhtiari, are of the least mixed descent of the ancient inhabitants. In the northern provinces, Turkic and Tatar influences are evident; Arab strains predominate in the southeast. Iran has a large rural population, found mainly in agrarian villages, although there are nomadic and seminomadic pastoralists throughout the country.
Islam entered the country in the 7th cent. A.D. and is now the official religion; about 90% of Iranians are Muslims of the Shiite sect. The remainder, mostly Kurds and Arabs, are Sunnis. Colonies of Zoroastrians (see Zoroastrianism) remain at Yazd, Kerman, and other large towns. In addition to Armenian and Assyrian Christian sects, there are Jews, Protestants, and Roman Catholics. Attempts have been made to suppress Babism and its successor, Baha’i, whose adherents constitute about 1% of Iran’s population; Sufism has also suffered from government restrictions under the Islamic republic. Other religious movements, such as Mithraism (see under Mithra) and Manichaeism, originated in Iran.
The principal language of the country is Persian (Farsi), which is written with the Arabic alphabet and spoken by about 60% of the people. Other groups speak Turkic dialects (25%), Kurdish, (10%), and Turkish, Armenian, and Arabic. Among the educated classes, English and French are spoken.
Iran is one of the oldest nations in the world, with a history dating back tens of thousands of years. The country’s first great city, Susa, was built on the central plateau around 3200 B.C.
In 559 B.C., the Persian Empire arose in southwestern Iran and conquered the Mesopotamians and Egyptians. The empire eventually extended from the Mediterranean Sea to what is now Pakistan, but it was conquered by the Greeks in 330 B.C.
Around 260 B.C., nomads called Parni ousted the Greeks and ruled for some 500 years. The Sassanids came into power in A.D. 224, and in A.D. 642, Persia became part of the Islamic Empire. In 1501, the kings, or shahs, of the Safavid Empire began their reign.
In the late 18th century, foreign powers, including Russia and Britain, took control of parts of Persia. In 1921, a Persian army officer named Reza Khan took control and sought to end outside influence. In 1935, he renamed the country Iran. His son, Mohammad Reza Pahlavi, became shah in 1941.
In 1979, many Iranians who felt Pahlavi was corrupt forced him to flee, ending the reign of the shahs in Iran. Since then, religious leaders have ruled the country. The first was Ayatollah Ruhollah Khomeini, whose ten years in power were marked by a long war with Iraq and tensions with the United States and many other nations. Imam Khomeini died in 1989, but much of those tensions still exist today.
Iran is a theocratic Islamic republic governed under the constitution of 1979 as amended. Appointed, rather than elected, offices and bodies hold the real power in the government. The supreme leader, who effectively serves as the head of state, is appointed for life by an Islamic religious advisory board (the Assembly of Experts). The supreme leader oversees the military and judiciary and appoints members of the Guardian Council and the Expediency Discernment Council. The former, some of whose members are appointed by the judiciary and approved by parliament, works in close conjunction with the government and must approve both candidates for political office and legislation passed by parliament. The latter is a body responsible for resolving disputes between parliament and the Guardian Council over legislation. The president, who is popularly elected for a four-year term, serves as the head of government. The unicameral legislature consists of the 290-seat Islamic Consultative Assembly, whose members are elected by popular vote for four-year terms. Administratively, Iran is divided into 30 provinces.