The holotype specimen, MOR 691 (Museum of the Rockies), was found by Robert W. Harmon in Glacier County, in the territory of the Blackfoot, in sandstone of the Upper Two Medicine Formation, a layer about 74 million years old.

The genus name Montanazhdarcho was first given informally in 1993 by Kevin Padian, Armand de Ricqlès, and Jack Horner.

[4] The fossil is largely uncompressed and that of an adult exemplar, as established by a study of the bone by de Ricqlès.

[1][2] Montanazhdarcho was by the authors assigned to the Azhdarchidae, mainly based on the elongated form of the neck vertebra.

Compared to other azhdarchids however, it was small; the fragments of humerus, radius, and carpal suggest an animal with a 2.5 m (8.2 ft) wingspan.