The Islamic Republic of Iran (Jomhuri-ye Eslami-ye Iran) covers 636,300 square miles (1,648,000 square kilometres) in southwestern Asia. It is bounded on the north by Azerbaijan, Armenia, Turkmenistan, and the Caspian Sea, on the east by Pakistan and Afghanistan, on the south by the Persian Gulf and the Gulf of Oman, and on the west by Turkey and Iraq. Iran also controls about a dozen islands in the Persian Gulf. More than 30 percent of its 4,770-mile (7,680-kilometre) boundary is seacoast. The capital is Tehran (Teheran).



Iran is the only country in the Middle East that uses the Islamic solar calendar, which originated before the beginning of the Persian Empire (550 BC). After the conversion of the vast majority of Iranians to Islam, the ancient Iranian calendar was adjusted to begin with the year of the Prophet Muhammad's immigration to Medina (the hijrah), equivalent to AD 622 in the Gregorian calendar. To convert from the Islamic solar calendar to the Gregorian, 621 or 622 years, depending on the time of year, are added to the Iranian year. (For example, the Iranian year 1361 began on March 21, 1982, and ended on March 20, 1983.) No-ruz (New Year's Day) falls on March 21, the vernal equinox. The Arabic lunar calendar is used for religious observances.

Iran has played an important role in the Middle East, as an  power and as a factor in rivalries between East and West. Its strategic position and its vast resources, including petroleum and natural gas, make it a nation to be reckoned with in the modern world.