, one of the major rivers of Siberia, which flows from sources in the Altai Mountains to the Gulf of Ob and the Kara Sea of the Arctic Ocean. Its course is 3,680 km/2,287 miles long and 5,410 km/3,362 miles long if its main left-bank affluent, the Irtysh [see irtis̲h̲ in Suppl.] is included. Its whole basin covers a huge area of western Siberia.
In early historic times, the lands along the lower and middle Ob were thinly peopled with such groups as the Samoyeds and the Ugrian Voguls and Ostiaks (in fact, the indigenous population of these regions today, only…