State flag of Iran (1964–1980)

Iran, officially the Islamic Republic of Iran (IRI) and also known as Persia, is a country in West Asia. It borders Iraq to the west, Turkey, Azerbaijan, and Armenia to the northwest, the Caspian Sea to the north, Turkmenistan to the northeast, Afghanistan to the east, Pakistan to the southeast, and the Gulf of Oman and the Persian Gulf to the south. Iran ranks 17th globally in both geographic size and population and is the sixth-largest country in Asia. Iran is officially an Islamic republic, divided into five regions with 31 provinces. Tehran is the nation's capital, largest city and financial centre. A cradle of civilisation, Iran was inhabited by various peoples, including the Elamites from 3200 BCE in the southwest, before the arrival of the Iranian peoples. A large part of Iran was first unified as a political entity by the Medes under Cyaxares in the 7th century BCE and reached its territorial height in the 6th century BCE, when Cyrus the Great founded the Achaemenid Empire. Alexander the Great conquered the empire in the 4th century BCE. An Iranian rebellion in the 3rd century BCE established the Parthian Empire, which later liberated the country. In the 3rd century CE, the Parthians were succeeded by the Sasanian Empire, whose era was considered a golden age in the history of Iranian civilisation. Ancient Iran saw some of the earliest developments of writing, agriculture, urbanisation, religion and administration. Once a centre for Zoroastrianism, Muslims conquered the region in the 7th century, leading to the Islamisation of Iran. The literature, philosophy, mathematics, medicine, astronomy and art which blossomed during the Sasanian era were renewed during the Islamic Golden Age and Iranian Intermezzo, when a series of Iranian Muslim dynasties ended Arab rule, revived the Persian language, and ruled the country. This era was followed by Seljuk and Khwarazmian rule, Mongol conquests and the Timurid Renaissance from the 11th to 14th centuries. In the 16th century, the native Safavid dynasty re-established a unified Iranian state with Twelver Shia Islam as the official religion. During the Afsharid Empire in the 18th century, Iran was a leading world power, but it lost this status after the Qajars took power in the 1790s. The early 20th century saw the Persian Constitutional Revolution and the establishment of the Pahlavi dynasty by Reza Shah, who ousted the last Qajar Shah in 1925. Attempts by Mohammad Mosaddegh to nationalise the oil industry led to the Anglo-American coup in 1953. The Iranian Revolution in 1979 overthrew the monarchy, and the Islamic Republic of Iran was established by Ruhollah Khomeini, the country's first supreme leader. In 1980, Iraq invaded Iran, sparking the eight-year-long Iran–Iraq War which ended in a stalemate. Iran is a threshold state with one of the most scrutinised nuclear programs it claims is solely for civilian purposes. This claim has been disputed by Israel and the Western world. In 2025, Israeli strikes on Iran escalated tensions into the Iran–Israel war. Iran is an Islamic theocracy governed by elected and unelected institutions, with ultimate authority vested in the Supreme Leader. While Iran holds elections, key offices—including the head of state and military—are not subject to public vote. The Iranian government has been regarded by some as authoritarian and criticised for its human rights record, including restrictions on freedom of assembly, expression, and the press, as well as its treatment of women, ethnic minorities, and political dissidents. International observers have raised concerns over the fairness of its electoral processes, especially the vetting of candidates by unelected bodies such as the Guardian Council. Iran maintains a centrally planned economy with significant state ownership in key sectors, though private enterprise exists alongside. Iran is a major regional power, due to its large reserves of fossil fuels (including the world's second largest natural gas supply and third largest proven oil reserves), its geopolitically significant location, and its role as the world's focal point of Shia Islam. Iran is a founding member of the United Nations, OIC, OPEC, and ECO as well as a current member of the NAM, SCO, and BRICS. Iran has 28 UNESCO World Heritage Sites (the 10th-highest in the world) and ranks 5th in intangible cultural heritage or human treasures.