Rwansar Lake is one of the fifty main tourist attractions in the Kermashan province, East Kurdistan. This tourist place is a natural spring located in Rwansar, and due to the abundance of water, a large pool has been built in front of it. The extra water is the main source of the Karasu River which is one of the largest and longest rivers in the Kermashan Province.

According to research, Rwansar Lake is 40000 years old and has registered as a natural heritage site of Iran in 2008. The water of this lake originates from Mount Shaho and in a rainy year more than 6000 liters of water per second was discharged, which caused the formation of a large river that after passing twenty kilometers with several other rivers to form the Karasu River.

In addition to providing drinking water to the entire Rwansar City, the Rwansar Lake also provided water for agriculture in dozens of hectares of land in Kermashan province. In the past three years, due to the drilling of six deep wells at the foot of Shaho Mountain and on the water sources of Rwansar, to supply water to the cities of Paveh and Jawanro, the water of Rwansar has decreased and dried up in summer.

In addition to being home to tens of thousands of fish, many species of birds, including geese, squirrels, Ukrainian swans, etc. have made this lake their habitat and visit it in spring. In recent years, thousands of fish have died and many poultry has migrated permanently.

With the revival of the springs in autumn, thousands of fish appeared in the lake again, so it is suspected that these fish hid in the underground pools inside of the mountain in the summer and returned to the lake again.

Rwansar is located northwest of Kermashan province at the foot of Shaho Mountain. The city is located 64 kilometers from the provincial capital, Kermashan. Jawanro is located 22 kilometers west of Rwansar. Most of the people of Rwansar speak Sorani and Ardalani dialects.