The Angara River (Buryat: Ангар, Angar, lit. "Cleft"; Russian: Ангара́, Angará) is a 1,779-kilometer-long (1,105 mi) river in Siberia, which traces a course through Russia's Irkutsk Oblast and Krasnoyarsk Krai. It is the river that drains Lake Baikal and is the headwater tributary of the Yenisei River. It was formerly known as the Lower or Nizhnyaya Angara (distinguishing it from the Upper Angara). Below its junction with the Ilim, it was formerly known as the Upper Tunguska (Russian: Верхняя Тунгуска, Verkhnyaya Tunguska, distinguishing it from the Lower Tunguska) and, with the names reversed, as the Lower Tunguska.