Iran, officially Islamic Republic of Iran, formerly Persia, Country, Middle East, southwestern Asia. Area: 629,674 sq mi (1,630,848 sq km). Population: (2026 est.) 87,312,000. Capital: Tehrān. Persians constitute the largest ethnic group; other ethnic groups include Azerbaijanians, Kurds, Lurs, Bakhtyārī, and Baloch. Languages: Persian (Farsī; official), numerous others. Religions: Islam (official; predominantly Shiʿi); also Zoroastrianism. Currency: rial. Iran occupies a high plateau, rising higher than 1,500 feet (460 metres) above sea level, and is surrounded largely by mountains. More than half of its surface area consists of salt deserts. About one-tenth of its land is arable, and another one-fourth is suitable for grazing. Iran’s rich petroleum reserves account for about one-tenth of world reserves and are the basis of its economy. It is a unitary Islamic republic with one legislative house and several oversight bodies dominated by clergy. The head of state and government is the president, but political and religious authority is held by the rahbar, often referred to as the supreme leader, who is chosen by a body of Islamic jurists and who oversees virtually all functions of government directly or indirectly.
Human habitation in Iran dates to some 100,000 years ago, but recorded history began with the Elamites c. 3000 bce. The Medes flourished from c. 728 but were overthrown in 550 by the Persians, who were in turn conquered by Alexander the Great in the 4th century bce. The Parthians created an empire that lasted from 247 bce to 226 ce, when control passed to the Sāsānian dynasty. Various Muslim dynasties ruled from the 7th century. In 1501 the Ṣafavid dynasty was established and lasted until 1736. The Qājār dynasty ruled from 1796, but in the 19th century the country was economically controlled by the Russian and British empires. Reza Khan seized power in a coup in 1921. His son Mohammad Reza Shah Pahlavi alienated religious leaders with a program of modernization and Westernization and was overthrown in 1979; Shiʿi cleric Ruhollah Khomeini then set up an Islamic republic, and Western influence was suppressed. The destructive Iran-Iraq War of the 1980s ended in a stalemate. Ali Khamenei succeeded Khomeini as Iran’s supreme leader in 1989, with popularly elected presidents operating under his authority. Since the 1990s, periods of openness and reform have alternated with conservative policies. Iran’s nuclear program has caused international tensions, including the imposition of economic sanctions on Iran and a military attack by Israel and the U.S. in 2025. Mass protests against the Iranian regime, particularly in 2022–23 and 2025–26, were harshly suppressed. The U.S. and Israel launched airstrikes on Iran in February 2026, killing Khamenei; Iran retaliated with missile and drone strikes across the region. Mojtaba Khamenei was appointed to succeed his father as supreme leader.
