[2] In 1981 and 1994, Mark Goodwin of the University of California Museum of Paleontology excavated limb bones and a vertebra near Rudyard in the north of Montana, at a site originally discovered by Kyoko Kishi.

After a school class found some more bones, in 2007 and 2008 a team of the Museum of the Rockies secured the remainder of a hadrosaur skeleton, among which the skull.

The fossil was donated to the Museum of the Rockies by land owners Nolan and Cheryl Fladstol; and John and Claire Wendland.

[3][4][5] In 2015, the type species Probrachylophosaurus bergei was named and described by Elizabeth A. Freedman Fowler and Jack Horner.

Adding the traits of Probrachylophosaurus to two earlier datasets of cladistic analyses, resulted in slightly conflicting positions.

[2] The revised analysis of Albert Prieto-Márquez resulted in the following evolutionary tree:[2] Iguanodon Bactrosaurus Hadrosaurus Wulagasaurus Corythosaurus Secernosaurus Kritosaurus Gryposaurus Acristavus Probrachylophosaurus Brachylophosaurus Maiasaura Edmontosaurus Prosaurolophus Saurolophus The describing article also published the result of histological research of the bone structure of the left shinbone of the type specimen.

This bone showed fourteen LAGs, lines of arrested growth, that likely represented yearly seasons of low food intake.

The distance between the lines indicated this individual had not yet reached its maximum size, but closely approached it, proof that it was not simply a subadult Brachylophosaurus specimen with a small crest.