The Ob River also Obi, is a major river in western Siberia

Siberia

Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

, Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

 and is the world's seventh longest river. It is the westernmost of the three great Siberia

Siberia

Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

n river

River

A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

s that flow into the Arctic Ocean (the other two being the Lena River

Lena River

The Lena is the easternmost of the three great Siberian rivers that flow into the Arctic Ocean . It is the 11th longest river in the world and has the 9th largest watershed...

 and the Yenisei River

Yenisei River

Yenisei , also written as Yenisey, is the largest river system flowing to the Arctic Ocean. It is the central of the three great Siberian rivers that flow into the Arctic Ocean...

).
The Gulf of Ob

Gulf of Ob

The Gulf of Ob is a gigantic bay of the Arctic Ocean, located in Northern Russia at the head the mouth of the Ob River....

 is the world's longest estuary

Estuary

An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....

.
The Ob is known to the Khanty people

Khanty people

Khanty / Hanti are an indigenous people calling themselves Khanti, Khande, Kantek , living in Khanty-Mansi Autonomous Okrug, a region historically known as "Yugra" in Russia, together with the Mansi. In the autonomous okrug, the Khanty and Mansi languages are given co-official status with Russian...

 as the As, Yag, Kolta and Yema; to the Nenets people

Nenets people

The Nenets are an indigenous people in Russia. According to the latest census in 2002, there are 41,302 Nenets in the Russian Federation, most of them living in the Yamalo-Nenets Autonomous Okrug and Nenets Autonomous Okrug...

 as the Kolta or Kuay; and to the Siberian Tatars

Siberian Tatars

Siberian Tatars refers to the indigenous Siberian population of the forests and steppes of South Siberia stretching from somewhat east of the Ural Mountains to the Yenisey river...

 as the Umar or Omass.
The Ob forms 16 miles (25.7 km) southwest of Biysk

Biysk

Biysk is a city in Altai Krai, Russia. It is the second largest city of the krai . Population: -Geography:Biysk is situated in southwestern Siberia, on the Biya River . The city is called "the gates to the Altai Mountains", because of its position comparatively not far from this range...

 in Altai Krai

Altai Krai

Altai Krai is a federal subject of Russia . It borders with, clockwise from the south, Kazakhstan, Novosibirsk and Kemerovo Oblasts, and the Altai Republic. The krai's administrative center is the city of Barnaul...

 at the confluence of the Biya

Biya River

The Biya River is a river in the Altai Republic and Altai Krai in Russia. It forms the Ob River as it joins the Katun River. The Biya River is 301 km long; the area of its drainage basin is 37,000 km². It flows out of the Teletskoye Lake. The river freezes up in the mid-November to early December...

 and Katun rivers.