The Zayanderud River is the longest river in Isfahan Province, Iran. It flows for about 400 kilometers, originating from the Zardkuh Mountains and eventually emptying into the Maharloo Lake. The river is crucial for irrigation and provides water to the surrounding agricultural areas. Historically, the Zayanderud has played a significant role in the development of Isfahan, a city known for its rich culture and architecture. The river has also been a vital source of water for local industries and has supported the region's economy for centuries.