Gilan province is enclosed as the flag-shaped body by the Alborz Mountains in the West and the plains of Gilan in South. In general, this province is isolated from the rest of Iran by Alborz Mountains and Talesh Mountains and it is considered as the southern part of the Caspian Sea. Altitudes in the province are divided into two parts western mountains ranges and eastern mountains ranges.

Western mountains ranges: Including Talesh Mountains, Masouleh, mountain ridges, thousands River valley, Astara to Manjil Strait with north-south direction, is a series of asymmetric parallel folds that has seprated Gilan from Ardabil and Zanjan and Astara and Talesh are also located on the eastern slopes of the mountains. High mountains of this part include  Baqr and daq mountains  with an altitude of 3,300 meters and Masouleh Mountain with a height of 3050 meters. An eastern mountain ranges:

It includes roughs of Deilaman, Lahijan, Ammarlou and Khazran and is a series of asymmetric parallel folds with western- eastern direction which is spread from White River Valley to the mountains of the province Mazandaran. Steep gradient of slopes is towards the Caspian Sea and low gradient is to the Shahrood valley. From the important mountains of the region we can name (Dorfak Mountain) with a height of 2,705 meters, Natesh Mountains and Clay Pits. Erosion of flowing water has created numerous valleys. Besides the Alborz Mountains, plains in the province of Gilan have special importance.

Plains in the province are divided to two parts: eastern plains and central plains. Eastern plain is located like a strip between the coast of the Caspian Sea and Dorfak Mountain the northern slopes of the western Alborz Mountain with low area which is directly affected by many coastal alluvial rivers with flood characteristics. Central Plains in the form of a triangle have widely been formed between Hashim shrine, Anzali and Chamkhaleh.