From geographical and topographical point of view, Ilam province is consisting of southern plains continuing of Mesopotamian plains, and Zagros oak forests including highland heights. The southern plains consist of calcareous and chalky soils, and the highland heights consist of limestone, sandstone, and conglomerate and rocky mountains. The fertile plains suitable for agriculture are located in this area. Generally the north and northeast areas of the province are mountainous and the west and southwest are composed of lowlands. The most important mountains of Ilam are Kabir-kuh and Dinar-kuh. From climatic point of view, Ilam province is among the warm regions of the country, but due to altitudes, the temperature differences and rainfall among the northern, southern and western parts of the province are great. So the province enjoys three different types of climate : 1. The mountainous areas of the north and northeastern are relatively cold with long winters. Average annual rainfall is over 500 mm and the minimum temperature falls to 15 degrees below zero in winter season. 2. The plain areas of the west and southwest are warm. The average annual rainfall is about 200 mm and the maximum temperature reaches 45 °c. 3. The central region enjoys a mild climate. The minimum temperature falls to 5 degree below zero in the winter and the maximum temperature reaches 40 degrees centigrade. The province has a wide variety of climate because of its latitude, altitudes, deserts of Saudi Arabia, Khuzestan plain, plains of Iraq and local winds.