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

It takes the name from the settlement of Fort Simpson, and was first described in well Briggs Turkey Lake No.

[2] The Fort Simpson Formation is composed of grey shale and mudstone.

The Fort Simpson Formation reaches a thickness of over 1,000 metres (3,280 ft) in the sub-surface of the Mackenzie River plain.

[1] It extends from northern Alberta to south-western northwest Territories and in north-eastern British Columbia (north of Peace River Arch).