Tar Lake, 30 kilometers east of Damavand is located in central Alborz Mountains. The maximum length of the lake is one kilometer to the west – south east and a maximum width of that is 600 meters in an East – West. In the East of Tar Lake hides another small lake called Havir Lake, which has 86 thousand square meters at an altitude of 2880 meters above sea level. The maximum length of the lake is 500 meters to the north – south and a maximum width is 180 meters in an East – West. This sweet water lake is formed by surface water accumulated from the northern highlands .
The most of drained water joined at the river called Dalichai which flows in the Mosha fault valley