Ishim River (Russian: Иши́м; Kazakh: Есіл) is a river running through Kazakhstan and Russia. It is 2,450 kilometres (1,520 mi) long; its average discharge is 56.3 cubic metres per second (1,990 cu ft/s). It is a left tributary of the Irtysh River. The Ishim River is partly navigable in its lower reaches. The upper course of the Ishim passes through Astana, the capital of Kazakhstan. In Russia, the river travels through a vast marshland for its course, and has countless meanders and oxbow lakes.