Geography

Iran (Persia) is situated in southwestern Asia, bordering the Gulf of Oman, the Persian Gulf and the Caspian Sea, between Iraq and Pakistan. With an area of 1,648,000 square kilometres, Iran ranks 18th in size among the countries of the world, after Libya. It is about one-fifth the size of the continental United States, or the size of the United Kingdom, France, Spain, and Germany combined.

Borders

Located in southwestern Asia, Iran shares its northern borders with former Soviet Union republics Armenia (35 km), Azerbaijan (432 km) and Turkmenistan (992 km). These northern borders include nearly 650 kilometres of water along the southern shore of the Caspian Sea. Iran's western borders are with Turkey in the north (499 km) and Iraq in the south (1,458 km), terminating at the Shatt al Arab (which Iranians call the Arvand Rud). The Persian Gulf and Gulf of Oman littorals form the entire 1,770 kilometre southern border.

Topography

Iran consists of rugged, mountainous rims surrounding high interior basins.

Mountains

The main mountain chain is the Zagros Mountains, a series of parallel ridges interspersed with plains that bisect the country from northwest to southeast. Many peaks in the Zagros exceed 3,000 metres above sea level, and in the south-central region of the country there are at least five peaks that are over 4,000 metres. As the Zagros continue into southeastern Iran, the average elevation of the peaks declines dramatically to under 1,500 metres.

Rimming the Caspian Sea littoral is another chain of mountains, the narrow but high Alborz Mountains. Volcanic Mount Damavand (5,610 m), located in the centre of the Alborz, is not only the country's highest peak but also the highest mountain on the Eurasian landmass west of the Hindu Kush.

Plateau

The centre of Iran consists of several closed basins that collectively are referred to as the Central Plateau. The average elevation of this plateau is about 900 metres, but several of the mountains that tower over the plateau exceed 3,000 metres. The eastern part of the plateau is covered by two salt deserts, the Dasht-e Kavir (Great Salt Desert) and the Dasht-e Lut. Except for some scattered oases, these deserts are uninhabited.

Lowlands

Iran has only two expanses of lowlands: the Khuzestan Plain in the southwest and the Caspian Sea coastal plain in the north. The Persian Gulf coast south of Khuzestan and the Gulf of Oman coast have no real plains because the Zagros in these areas come right down to the shore.

The Khuzestan Plain is a roughly triangular-shaped extension of the Mesopotamia plain and averages about 160 kilometres in width. It extends for about 120 kilometres inland, barely rising a few metres above sea level, then meets abruptly with the first foothills of the Zagros. Much of the Khuzestan plain is covered with marshes.

The Caspian plain is both longer and narrower. It extends for some 640 kilometres along the Caspian shore, but its widest point is less than 50 kilometres, while at some places less than 2 kilometres separate the shore from the Alborz foothills.

Rivers

There are no major rivers in the country. Of the small rivers and streams, the only one that is navigable is the Karun (830 km long), which shallow-draft boats can negotiate from Khorramshahr to Ahvaz, a distance of about 180 kilometres. Other major rivers include the Kharkeh, which is 700 kilometres long; and the Zayandeh Rud, which is 400 kilometres long. Several other permanent rivers and streams also drain into the Persian Gulf, while a number of small rivers that originate in the northwestern Zagros or Alborz drain into the Caspian Sea.

On the Central Plateau, numerous rivers, most of which have dry beds for the greater part of the year, form from snow melting in the mountains during the spring and flow through permanent channels, draining eventually into salt lakes that also tend to dry up during the summer months.

There is a permanent salt lake: Lake Urmia in the northwest, whose brine content is too high to support fish or most other forms of aquatic life. Lake Urmia (also known as Lake Urmiyeh) is the traditional name, to which it has reverted after being called Lake Rezaiyeh under Mohammad Reza Shah. There are also several connected salt lakes along the Iran-Afghanistan border in the province of Baluchestan va Sistan.