The Yesilirmak River, also known as the Halys River in ancient times, is the longest river in Turkey. It flows for approximately 519 kilometers, originating from the Eastern Anatolia region and winding through various provinces before emptying into the Black Sea. The river plays a crucial role in the local ecosystem and agriculture. The Yesilirmak River is significant for its historical importance, as it was a vital waterway in ancient civilizations, including the Hittites and Phrygians. Today, it supports irrigation and provides water for nearby communities, contributing to the region's economy and biodiversity.