The Zab River originates in the Zagros Mountains in the central regions of West Azerbaijan Province and flows south. Zab river flows parallel to Piranshahr-Sardasht road. Near Sardasht, a dam has been built on the Zab River, which has created a lake behind the dam. After that the Zab River continues to flow into Iraq and eventually joins the Tigris River. The part of the Zab River that flows in Iran in the province of West Azerbaijan is called Little Zab.