The Oldman Formation is a stratigraphic unit of Late Cretaceous (Campanian stage) age that underlies much of southern Alberta, Canada.

They are upward-fining, lenticular to sheet-like bodies that are yellowish, steep-faced and blocky in outcrop.

The formation is about 40 metres (130 ft) thick at Dinosaur Provincial Park in southeastern Alberta.

It thickens toward the southwest, and northwestern Montana appears to have been the primary source of the sediments.

[3][4] The Oldman Formation was deposited during the middle Campanian, between about 77.5 and 76.5 million years ago.