|The Yesilirmak (from Turkish Yesil—green; known in antiquity as the Iris), a river in Turkey, has a course of approximately 418 kilometers. The area of its basin is around 20,000 square kilometers. The river rises in the mountains of northeast Turkey, flows northwest through narrow fertile valleys, and ends in the Black Sea, near the city of Samsun. The river's highest flow is from March to July, as snow melts in the mountains of Turkey, and its lowest flow is in November and December.|
The Yesilirmak River is an important source of drinking and irrigation water for northern Turkey, and since ancient times it cities flourished along its course. The area along the river basin is known for its historical treasures and numerous architectural monuments from pre-Hellenic, ancient Greek, and Roman eras, as well as from the early Ottoman empire. This region has been inhabited since prehistoric times by various civilizations, including the Hittites (second millennium BCE) and Phrygians (early first millennium BCE), and was once part of Pontus, a kingdom bordering the Black Sea, which flourished from the fourth century BCE until it became part of the Roman empire in 63 BCE.