Iran is situated in Southwest Asia, bordering the Gulf of Oman, the Persian Gulf, and the Caspian Sea, between Iraq and Pakistan. Iran is one of the world's most mountainous countries. Its mountains have helped to shape both the political and the economic history of the country for several centuries. The mountains enclose several broad basins, or plateaus, on which major agricultural and urban settlements are located. Until the twentieth century, when major highways and railroads were constructed through the mountains to connect the population centers, these basins tended to be relatively isolated from one another. Typically, one major town dominated each basin, and there were complex economic relationships between the town and the hundreds of villages that surrounded it. In the higher elevations of the mountains rimming the basins, tribally organized groups practiced transhumance, moving with their herds of sheep and goats between traditionally established summer and winter pastures. There are no major river systems in the country, and historically transportation was by means of caravans that followed routes traversing gaps and passes in the mountains. The mountains also impeded easy access to the Persian Gulf and the Caspian Sea.
With an area of 1,648,000 square kilometers, Iran ranks sixteenth in size among the countries of the world. Iran is about one-fifth the size of the continental United States, or slightly larger than the combined area of the contiguous states of California, Arizona, Nevada, Oregon, Washington, and Idaho.
Located in southwestern Asia, Iran shares its northern borders with former Soviet Union republics Armenia, Azerbaijan, and Turkmenistan. These borders extend for more than 2,000 kilometers, including nearly 650 kilometers of water along the southern shore of the Caspian Sea. Iran's western borders are with Turkey in the north and Iraq in the south, 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 kilometer southern border. To the east lie Afghanistan on the north and Pakistan on the south. Iran's diagonal distance from Azerbaijan in the northwest to Baluchestan va Sistan in the southeast is approximately 2,333 kilometers.
Iran (Persia) consists of rugged, mountainous rims surrounding high interior basins. 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 meters above sea level, and in the south-central region of the country there are at least five peaks that are over 4,000 meters. As the Zagros continue into southeastern Iran, the average elevation of the peaks declines dramatically to under 1,500 meters. Rimming the Caspian Sea littoral is another chain of mountains, the narrow but high Alborz Mountains. Volcanic Mount Damavand (5 671 m), located in the center 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.
The center 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 meters, but several of the mountains that tower over the plateau exceed 3,000 meters. 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.
Iran has only two expanses of lowlands: the Khuzestan Plain in the southwest and the Caspian Sea coastal plain in the north. The former is a roughly triangular-shaped extension of the Mesopotamia plain and averages about 160 kilometers in width. It extends for about 120 kilometers inland, barely rising a few meters 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 kilometers along the Caspian shore, but its widest point is less than 50 kilometers, while at some places less than 2 kilometers separate the shore from the Alborz foothills. 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.
There are no major rivers in the country. Of the small rivers and streams, the only one that is navigable is the Karun (830 Kilometres long), which shallow-draft boats can negotiate from Khorramshahr to Ahvaz, a distance of about 180 kilometers. Other major rivers include the Kharkeh, which is 700 kilometers long and flows into the Tigris; and the Zayandeh River, which is 300 kilometers 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 (the traditional name, also cited as Lake Urmiyeh, to which it has reverted after being called Lake Rezaiyeh under Mohammad Reza Shah), in the northwest, whose brine content is too high to support fish or most other forms of aquatic life. There are also several connected salt lakes along the Iran-Afghanistan border in the province of Baluchestan va Sistan.
Iran has a variable climate. In the northwest, winters are cold with heavy snowfall and subfreezing temperatures during December and January. Spring and fall are relatively mild, while summers are dry and hot. In the south, winters are mild and the summers are very hot, having average daily temperatures in July exceeding 38 °C (100 °F). On the Khuzestan plain, summer heat is accompanied by high humidity.
In general, Iran has an arid climate in which most of the relatively scant annual precipitation falls from October through April. In most of the country, yearly precipitation averages 25 centimeters or less. The major exceptions are the higher mountain valleys of the Zagros and the Caspian coastal plain, where precipitation averages at least 50 centimeters annually. In the western part of the Caspian, rainfall exceeds 100 centimeters annually and is distributed relatively evenly throughout the year. This contrasts with some basins of the Central Plateau that receive ten centimeters or less of precipitation annually.
More than one-tenth of the country is forested. The most extensive growths are found on the mountain slopes rising from the Caspian Sea, with stands of oak, ash, elm, cypress, and other valuable trees. On the plateau proper, areas of scrub oak appear on the best-watered mountain slopes, and villagers cultivate orchards and grow the plane tree, poplar, willow, walnut, beech, maple, and mulberry. Wild plants and shrubs spring from the barren land in the spring and afford pasturage, but the summer sun burns them away. According to FAO reports , the major types of forests that exist in Iran and their respective areas are:
More than 2,000 plant species are grown in Iran. The land covered by Iran’s natural flora is four times that of the Europe’s.
Wildlife of Iran includes its flora and fauna and their natural habitats. One of the most famous members of wildlife in Iran are the world's last surviving, critically endangered Asiatic Cheetah, which today are found nowhere else but in Iran. Iran had lost all its Asiatic Lion and the now extinct Caspian Tigers by the earlier part of the twentieth century. Bears in the mountains, wild sheep and goats, gazelles, wild asses, wild pigs, panthers, and foxes abound. Domestic animals include sheep, goats, cattle, horses, water buffalo, donkeys, and camels. The pheasant, partridge, stork, and falcon are native to Iran.
The Persian leopard is said to be the largest of all the subspecies of leopards in the world. The main range of this species in Iran closely overlaps with that of Bezoar Ibex. Hence, it is found throughout Alborz and Zagros mountain ranges, as well as smaller ranges within the Iranian plateau. Leopard population is very sparse, due to loss of habitat, loss of natural prey, and population fragmentation. Apart from Bezoar Ibex, wild sheep, boar, deer (either Maral red deer or roe deer), and domestic animals constitute leoprads' diet in Iran.
total: 1.648 million km²
land: 1.636 million km²
water: 12 000 km²
total: 5 440 km
border countries: Afghanistan 936 km, Armenia 35 km, Azerbaijan-proper 432 km, Azerbaijan-Nakhchivan exclave 179 km, Iraq 1 458 km, Pakistan 909 km, Turkey 499 km, Turkmenistan 992 km
2 440 km
note: Iran also borders the Caspian Sea (740 km)
contiguous zone: 24 nautical miles (44 km)
continental shelf: natural prolongation
exclusive economic zone: bilateral agreements, or median lines in the Persian Gulf
territorial sea: 12 nautical miles
petroleum, natural gas, coal, chromium, copper, iron ore, lead, manganese, zinc, sulfur
arable land: 10%
permanent crops: 1%
permanent pastures: 27%
forests and woodlands: 13%
other: 49% (1998 est.)
Irrigated land: 94,000 km² (1993 est.)
Natural hazards: periodic droughts, floods; dust storms, sandstorms; earthquakes along western border and in the northeast
Environment - current issues: air pollution, especially in urban areas, from vehicle emissions, refinery operations, and industrial effluents; deforestation; overgrazing; desertification; oil pollution in the Persian Gulf; wetland losses from drought; soil degradation (salination); inadequate supplies of potable water in some areas; urbanization.
Endangered species: As of 2001, 20 of Iran's mammal species and 14 bird species are endangered. Endangered species in Iran include the Baluchistan bear, Asiatic cheetah, Persian fallow deer, Siberian white crane, hawksbill turtle, green turtle, Oxus cobra, Latifi's viper, dugong, and dolphins. The Syrian wild ass has become extinct.