The source of the Kuloy is in the Lake Sonduzhskoye north-west of the town of Totma.

The first village (on the left bank) is Rogna, which was the starting point for timber rafting.

Downstream of the mouth of the Kundeba, the Kuloy turns north-west and eventually enters Arkhangelsk Oblast.

There, Kuloy River accepts two of its biggest tributaries: the Sivchuga from the left and the Kolenga from the right.

Downstream of the mouth of the Kolenga, the Kuloy sharply turns west.