The Kızılırmak, also known as the Halys River in ancient times, is the longest river in Turkey. It flows for about 1,355 kilometers, originating from the Eastern Anatolia region and emptying into the Black Sea. The river is significant for its historical importance and its role in the region's agriculture. The Kızılırmak is characterized by its reddish-brown color, which is due to the sediment it carries. It passes through several provinces, including Kayseri and Sivas, and supports various ecosystems along its banks. The river is also vital for irrigation and provides water for local communities.