Iran

I

Introduction

Iran, officially the Islamic Republic of Iran, country in southwestern Asia, located on the northeastern shore of the Persian Gulf. One of the world's most mountainous countries, Iran contains Mount Damāvand, the highest peak in Asia west of the Himalayas. The country’s population, while ethnically and linguistically diverse, is almost entirely Muslim. For centuries, the region has been the center of the Shia branch of Islam (see Shia Islam). Iran ranks among the world’s leaders in its reserves of oil and natural gas. As is the case in other countries in the petroleum-rich Persian Gulf region, the export of oil has dominated Iran’s economy since the early 20th century.

In the 6th century bc the territory of present-day Iran was the center of the Persian Empire, the world’s preeminent power at that time. For more than 2,000 years, the region’s inhabitants have referred to it by the name Iran, derived from the Aryan tribes who settled the area long ago. However, until 1935, when the Iranian ruler demanded that the name Iran be used, the English-speaking world knew the country as Persia, a legacy of the Greeks who named the region after its most important province, Pars (present-day Fārs). Iran was a monarchy ruled by a shah, or king, almost without interruption from 1501 until 1979, when a yearlong popular revolution led by the Shia clergy culminated in the overthrow of the monarchy and the establishment of an Islamic republic. See Islamic Revolution of Iran.

Iran lies at the easternmost edge of the geographic and cultural region known as the Middle East. The country is bordered on the north by Armenia, Azerbaijan, the Caspian Sea, and Turkmenistan; on the east by Afghanistan and Pakistan; on the south by the Gulf of Oman, the Strait of Hormuz, and the Persian Gulf; and on the west by Iraq and Turkey. Iran’s capital and largest city is Tehrān, located in the northern part of the country.

II

Land and Resources

Iran is the second largest country in the Middle East, after Saudi Arabia. It extends over a total area of 1,648,000 sq km (636,300 sq mi). The country is roughly triangular in shape, with its longest side extending in a slightly outward arc for 2,500 km (1,600 mi) from the border with Turkey in the northwest to the border with Pakistan in the southeast. The third point of the triangle lies in the northeast, about halfway along Iran’s border with Turkmenistan. Iran’s greatest extent from north to south is 1,600 km (1,000 mi) and from east to west is 1,700 km (1,100 mi).

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A

Natural Regions

Iran’s interior plateaus are almost completely surrounded by mountains. The main mountain system, the Zagros Mountains, cuts across the country for more than 1,600 km (1,000 mi) from northwest to southeast. With the exception of the Khūzestān coastal plain, which extends from the northern reaches of the Persian Gulf, the Zagros Mountains occupy all of western Iran. The central part of the range averages more than 340 km (210 mi) in width. Many peaks of the Zagros exceed 4,000 m (12,000 ft) in elevation; the highest is Zard Kūh (4,547 m/14,918 ft). Peaks rising above 2,300 m (7,500 ft) capture considerable moisture, which percolates down to the lower-lying basins as groundwater. These basins, ranging from about 1,200 to 1,500 m (about 4,000 to 5,000 ft) in elevation, contain fertile soil that traditionally has sustained diverse and intensive crop cultivation.

In Iran’s northern reaches, a steep, narrow mountain range, the Elburz Mountains, rims the entire southern coast of the Caspian Sea. This range extends more than 600 km (400 mi) in length and averages about 100 km (about 60 mi) in width. The country's highest peak, Mount Damāvand (5,670 m/18,602 ft), lies in the central part of the range. Several other peaks of the Elburz Mountains exceed 3,600 m (12,000 ft). The northern slopes of the range receive considerable rainfall throughout the year and support forests. A fertile coastal plain averaging 24 km (15 mi) in width lies between the Caspian Sea and the mountains. East of the Elburz Mountains is a series of parallel mountain ranges with elevations of 2,400 to 2,700 m (8,000 to 9,000 ft). These ranges are interspersed with many narrow, arable valleys. Several low mountain ridges, generally referred to as the eastern highlands, run along Iran’s eastern border.

Within this mountainous rim lies a series of basins known collectively as the central plateau. They include the Dasht-e Kavir, a huge salt-encrusted desert in north central Iran; the Dasht-e Lūt, a sand-and-pebble desert in the southeast; and several fertile oases.

The mountains of Iran constitute an active earthquake zone, and numerous minor earthquakes occur each year. Major earthquakes causing great loss of life and property damage also occur periodically. During the 18th century earthquakes twice leveled Tabrīz, the principal city in the northwest, killing at least 40,000 people on each occasion. Several severe earthquakes resulting in thousands of deaths have occurred since the mid-20th century. A devastating earthquake centered in the fault zone where the Elburz and Zagros mountains intersect in northwestern Iran killed an estimated 37,000 people in June 1990. A December 2003 earthquake in southern Iran destroyed much of the ancient city of Bam and killed more than 30,000 people. Several of Iran's highest mountains are volcanic cones; only Mount Damāvand and Kūh-e Taftān in southeastern Iran are active volcanoes, both periodically emitting gases near their summits.

B

Rivers and Lakes

Nearly all of Iran’s numerous rivers are relatively short, shallow streams unsuitable for navigation. The country’s only navigable river, the Kārūn, flows through the city of Ahvāz in the southwest. Most rivers rise in the mountainous regions and drain into the interior basins. Since ancient times, the region’s inhabitants have used the rivers for irrigation. Dams constructed in the 20th century on the Āb-e Dez, Karkheh, Kārūn, Sefid Rud, and other rivers have expanded the area under irrigation and also have provided a principal source of hydroelectricity. Three rivers form portions of Iran's international boundaries. The Aras River lies along the border with Armenia and Azerbaijan, the Atrek River borders Turkmenistan, and the Shatt al Arab, also known as the Arvandrud River, is part of the border with Iraq. Iran also shares the Caspian Sea, the world's largest inland body of water, with four other countries. Several smaller saltwater lakes lie entirely within Iran; the largest is Lake Urmia in the northwest. A few small freshwater lakes exist in high mountain valleys.

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