 From its origins as the "Kara-Irtysh" (Vast Irtysh, kara means Vast in Turkic languages but also black.But in the context and geographic terms usually refers vast) in the Mongolian Altay mountains in Xinjiang, China, the Irtysh flows northwest through Lake Zaysan in Kazakhstan, meeting the Ishim and Tobol rivers before merging with the Ob near Khanty-Mansiysk in western Siberia, Russia after .The name Black Irtysh ("Kara-Irtysh" in Kazakh, or "Cherny Irtysh" in Russian) is applied by some authors, especially in Russia and Kazakhstan, to the upper course of the river, from its source entering Lake Zaysan.