The Sefīd-Rūd (Persian: سفیدرود‎‎, pronounced: [sefiːdruːd], "White River" Azerbaijani: قزل اؤزؤن) is a river approximately 670 kilometres (416 mi) long, rising in northwestern Iran and flowing generally northeast to meet the Caspian Sea at Rasht. The river is Iran's second longest river after the Karun.Sefid Rud has cut a water gap through the Alborz Mountains, the Manjil gap, capturing two headwater tributaries and widening the valley between the Talesh Hills and the main Alborz range.