The drainage basin of the Oyat includes the southern parta of Podporozhsky and Lodeynopolsky Districts, the areas in the west of Vytegorsky and Babayevsky Districts of Vologda Oblast, as well as minor areas in the north of Tikhvinsky District of Leningrad Oblast.
The Oyat's drainage basin includes the southern regions of Podporozhsky and Lodeynopolsky Districts, the western portions of Vytegorsky and Babayevsky Districts in Vologda Oblast, as well as small areas in the northern part of Tikhvinsky District within Leningrad Oblast.