The Besa River Formation is a stratigraphical unit of Devonian age in the Western Canadian Sedimentary Basin.

[2] The Besa River Formation is composed primarily of dark shale.

The shale is slightly calcareous or siliceous and contains sponge spicules and radiolarians.

[1] The Besa River Formation reaches a maximum thickness of 1,655 metres (5,430 ft) in the foothills .

[1] The lower Besa River Formation is faulted and folded in the Northern Rockies.