The Karasuk (Russian: Карасук) is a river in the Karasuksky, Krasnozyorsky, Kochkovsky and Chulymsky districts, Novosibirsk Oblast, Russia.

[2] The Karasuk begins some 100 kilometres (62 mi) southwest of Novosibirsk, at 190 metres (620 ft) above sea level.

It flows in a southwesterly direction through a wide valley in the southern part of the Baraba Steppe ending in the eastern shore of lake Studyonoye at 105 metres (344 ft).

Some water may also branch off towards the north at Nizhnecheremoshnoye, via the Baganyonok (Russian: Баганёнок) tributary, to the Bagan River.

Other inhabited places near the banks of the Karasuk include Kochki, Krasnaya Sibir, Chernovka, Reshety, Bukreyevo Pleso, Chernaki, Mayskoye, Mokhnaty Log, Gerbayevo, Krasnozyorskoye, Novy Baganyonok, Kaigorodsky and Studyonoye.