This is a major river in western Siberia, Russia, and the World’s 7th longest river. This river is 3,395 miles long, with a drainage area of 2,990,000 square kilometers and an average discharge of 12,475 cubic meters’ per-second. The Ob forms 16 miles southwest of Biysk in Altai Krai at the confluence of the Katun and Biya rivers.