Atrek

Atrek, river in north-eastern Iran. The Atrek flows into the Caspian Sea on the sea’s Asian side, and its source is a spring in the mountains north-west of Mashhad called Kora Kazan, or “Black Cauldron”. The river traverses a straight-line distance of 480 km (298 mi), but the river's actual course runs for 669 km (416 mi). Its lower course forms part of the boundary between south-western Turkmenistan and north-eastern Iran. There are no major cities on the Atrek's banks, but the Turkmen town of Hasan Kuli on the Caspian Sea is 24 km (15 mi) north of the river's mouth.