Semnan province is one of the historical cities in Iran. It is located in the southern mountain sides of Alborz with neighbors such as Mazandaran and Golestan provinces in north, Isfahan in south, Khorasan in east, and Tehran in west. The highlands of Semnan province are reduced from north to the south and lead to desert. The major cities are Semnan, Shahrood, Damghan, Garmsar, and Mahdishahr.
There are various land conditions due to being next to Alborz Mountains and flat land in desert. The climate in the southern part is hot and dry, in central areas is mild and in the north east is cold and dry. But in the northern part it is rather cold. This variation in climate causes the different plants to be grown in Semnan province. So, wherever we go ahead from desert areas to the northern and southern slopes of Alborz Mountains, the plants are related to the desert region and semi-desert one, but in north and northwest, the plants are related to semi-cold region and cold one.