It flows in a predominant easterly direction, frequently widening into lakes which are separated by short stretches of stream with many rapids and falls.

It flows through a region of low granite hills, mixed with considerable areas of muskeg.

[6] After Badesdawa Lake, the river flows in a northeasterly direction to Ozhiski Lake, through land that is overlain by heavy deposits of glacial drift, often between 15 and 18 metres (50 and 60 ft) thick, while forming ridges rising from 21 to 30 metres (70 to 100 ft) above the general level in some places, with areas of muskeg and low sand-covered flats between them.

The dominant forest trees are black spruce, tamarack, and occasional stands of white spruce, as well as balsam and aspen poplar, with Banksian pine and white birch on some of the ridges.

[6] At Ozhiski Lake, the Otoskwin River continues north for 24 kilometres (15 mi) through many strong rapids with a high average flow rate.