the Ob near BarnaulThe watershed of the Ob, shown in yellow
The Ob is a river in Siberia. Together with the Lena and the Yenisei, it is one of the most important rivers of Siberia. Depending upon how its length is measured, it can be between 3.650 km and 6.210 km long. Some important cities on the banks of the river include Novosibirsk (Russia's third largest city), Barnaul, Kolpashevo, Nizhnevartovsk, Surgut, Khanty-Mansiysk, Beryozovo, Labytnangi, and Salekhard. The Irtysh is the Ob river's main tributary. Other tributaries include the Omsk, Parabel, Chaya, Tobol and Ishim.
The Gulf of Ob is the world's longest estuary.
Names
The name Ob is based on the Russian name of Обь. The Ob is known to the Khanty people as the As, Yag, Kolta and Yema; to the Nenets people as the Kolta or Kuay; and to the Siberian Tatars as the Umar or Omass.
