The McMurray Formation is a stratigraphic unit of Early Cretaceous age (late Barremian to Aptian stage) of the Western Canada Sedimentary Basin in northeastern Alberta. It takes the name from Fort McMurray and was first described from outcrops along the banks of the Athabasca River 5 kilometres (3.1 mi) north of Fort McMurray by F.H. McLearn in 1917. It is a well-studied example of fluvial to estuarine sedimentation, and it is economically important because it hosts most of the vast bitumen resources of the Athabasca Oil Sands region.