Iran, officially the Islamic Republic of Iran and formerly known internationally as Persia until 1935, is a country in Central Eurasia, located on the northeastern shore of the Persian Gulf and the southern shore of the Caspian Sea. Since 1949, both the names "Persia" and "Iran" are used, however, Iran is used for an official and political context.  Iran is the eighteenth largest country in the world. Its area roughly equals that of the United Kingdom, France, Spain, and Germany combined, or slightly less than the state of Alaska. Its borders are with Azerbaijan(432 km/268 mi) and Armenia (35 km/22 mi) to the north-west; the Caspian Sea to the north; Turkmenistan (992 km/616 mi) to the north-east; Pakistan (909 km/565 mi) and Afghanistan (936 km/582 mi) to the east; Turkey (499 km/310 mi) and Iraq (1,458 km/906 mi) to the west; and finally the waters of the Persian Gulf and the Gulf of Oman to the south. Iran's area is 1,648,000 km² (approximately 636,300 sq mi). Iran consists of the Iranian Plateau with the exception of the coasts of the Caspian Sea and Khuzestan. It is one of the world's most mountainous countries, its landscape dominated by rugged mountain ranges that separate various basins or plateaux from one another. The populous western part is the most mountainous, with ranges such as the Caucasus, Zagros and Alborz Mountains; the latter contains Iran's highest point, Mount Damavand at 5,610 m (18,405 ft), which is not only the country's highest peak but also the highest mountain on the Eurasian landmass west of the Hindu Kush. The Northern part of Iran is covered by dense rain forests called Shomal or the Jungles of Iran. The eastern part consists mostly of desert basins such as the Dasht-e Kavir, Iran's largest desert, in the north-central portion of the country, and the Dasht-e Lut, in the east, as well as some salt lakes. This is because the mountain ranges are too high for rain clouds to reach these regions. The only large plains are found along the coast of the Caspian Sea and at the northern end of the Persian Gulf, where Iran borders the mouth of the Shatt al-Arab (or the Arvand Rud) river. Smaller, discontinuous plains are found along the remaining coast of the Persian Gulf, the Strait of Hormuz and the Sea of Oman.

Iran's climate ranges from arid or semiarid, to subtropical along the Caspian coast and the northern forests. On the northern edge of the country (the Caspian coastal plain) temperatures nearly fall below freezing and it remains humid for the rest of the year. Summer temperatures rarely exceed 29 °C (85 °F). Annual precipitation is 680 mm (27 in) in the eastern part of the plain and more than 1,700 mm (67 in) in the western part. To the west, settlements in the Zagros basin experience lower temperatures, severe winters with below zero average daily temperatures and heavy snowfall. The eastern and central basins are arid, with less than 200 mm (eight in) of rain, and have occasional deserts. Average summer temperatures exceed 38 °C (100 °F). The coastal plains of the Persian Gulf and Gulf of Oman in southern Iran have mild winters, and very humid and hot summers. The annual precipitation ranges from 135 to 355 mm (five to fourteen inches). Iran's wildlife is composed of several animal species including bears, gazelles, wild pigs, wolves, jackals, panthers, Eurasian lynx, and foxes. Other domestic animals include, sheep, goats, cattle, horses, water buffalo, donkeys, and camels. The pheasant, partridge, stork, eagles and falcon are also native to Iran.