The Bolshoy Yugan is a river in Russia, it flows through the territory of Surgutsky and Nefteyugansky Districts of Khanty-Mansi Autonomous Okrug. A left tributary of the Ob, it discharges into the Yuganskaya Ob, a branch of the Ob. The length of the river is 1,063-kilometre (661 mi), its basin area is 34,700-square-kilometre (13,400 sq mi). The average annual water consumption at 118-kilometre (73 mi) from the mouth of the river is 177.67-cubic-metre-per-second (6,274 cu ft/s). Its source is in the Vasyugan Swamp, it flows through the wetlands of the West Siberian Plain. It has many tributaries, the largest of which is the right Maly Yugan. There are about 8,000 lakes in the basin, their total area is 545-square-kilometre (210 sq mi). The river is snow fed. It stays frozen from October to early May. Major settlements from the mouth to the source: Yugan, Maloyugansky, Ugut, Kogonchiny, Kayukovy, Taurova, Taylakovo, Larlomkiny.
