Ob (river) in the context of "Western Siberia"

A tributary, or an affluent, is a stream or river that flows into a larger stream (main stem or "parent"), river, or a lake. A tributary does not flow directly into a sea or ocean. Tributaries, and the main stem river into which they flow, drain the surrounding drainage basin of its surface water and groundwater, leading the water out into an ocean, another river, or into an endorheic basin.

The Irtysh, a tributary of the Ob river, is the longest tributary river in the world with a length of 4,248 km (2,640 mi).The Madeira River is the largest tributary river by volume in the world with an average discharge of 31,200 m/s (1.1 million cu ft/s).

The Lena is a river in the Russian Far East and is the easternmost river of the three great rivers of Siberia which flow into the Arctic Ocean, the others being Ob and Yenisey. The Lena River is 4,294 km (2,668 mi) long and has a capacious drainage basin of 2,490,000 km (960,000 sq mi); thus the Lena is the eleventh-longest river in the world and the longest river entirely within Russia. Geographically, permafrost underlies all the Lena River's catchment and it is continuous in over 75 percent of the basin.

Khanty (also spelled Khanti or Hanti), previously known as Ostyak (/ˈɒstjæk/), is a branch of the Ugric languages composed of multiple dialect continua. It is varyingly considered a language or a collection of distinct languages spoken in the Khanty-Mansi and the Yamalo-Nenets Autonomous Okrugs in Siberia. It belongs to the wider Uralic language family. There were thought to be around 7,500 speakers of Northern Khanty and 2,000 speakers of Eastern Khanty in 2010, with Southern Khanty being extinct since the early 20th century. The number of speakers reported in the 2020 census was 13,900.

The Khanty language has many dialects. The western group includes the Obdorian, Ob, and Irtysh dialects. The eastern group includes the Surgut and Vakh-Vasyugan dialects, which in turn are subdivided into 13 other dialects. All these dialects differ significantly from each other by phonetic, morphological, and lexical features to the extent that the three main "dialects" (northern, southern and eastern) are mutually unintelligible. Thus, based on their significant multifactorial differences, Eastern, Northern and Southern Khanty may be considered separate but closely related languages.

The Irtysh (/ɜːrˈtɪʃ, ˈɪərtɪʃ/) is a river in Russia, China, and Kazakhstan. It is the chief tributary of the Ob and is also the longest tributary in the world.

The river's source lies in the Mongolian Altai in Dzungaria (the northern part of Xinjiang, China) close to the border with Mongolia.