Spread across an area of 5,410 kilometres, the Ob-Irtysh stretches across Russia, Kazakhstan, China, Mongolia. The Ob river is the longest in Russia and has its origins in the Asian Altai Mountains. The Ob basin covers different types of regions—coniferous forests, deserts, plains and grasslands. The river starts from the glaciers of the Altai Mountains in Xinjiang, China, flows across Kazakhstan, crosses the West Siberian Plain and moves on to meet Ob River around Khanty-Mansiysk, Siberia.