Irtysh

River in central Asia, crossing the territory of China, Kazakhstan, and the Russian Federation; length 4,248 km/2,640 mi. The Irtysh is the chief tributary of the Ob. It rises in the Altai Mountains in Sinkiang Uighur (China), flows northwest through Lake Zaisan in Kazakhstan, then turns north to join the Ob south of Barnaul. Almost the whole of the river is navigable. The main goods transported on it are timber, grain, and coal. The chief ports are Omsk, Semipalatinsk, Pavlodar, Ust-Kamenogorsk, and Tobolsk.

On its course, the Irtysh passes through regions with rich deposits of non-ferrous metals, coal, and salt. Ust-Kamenogorsk and Bukhtarma hydroelectric power stations were built on the river in the 1950s. The Irtysh–Karaganda Canal (length 451 km/280 mi) supplies water to the industries of Karaganda and Ekibastuz, and for agricultural irrigation.