Few researchers have attempted rigorous cladistic analyses of fossil ochotonids (pikas), largely due to the paucity and morphological conservativism of the fossils. However, pikas were diverse and widespread during the Cenozoic, and we therefore explore the applicability of cladistic analysis utilizing dental characters, which comprise most of their fossil record. We used abundant Barstovian ochotonid specimens from Hepburn's Mesa, Montana, and previously described Miocene material to construct a phylogeny and explore congruencies among the phylogenetic, stratigraphic, and geographic occurrence of Oreolagus from the western United States. Maximum parsimony analysis was conducted using 13 morphological characters. Stratigraphic and geographic occurrences of Oreolagus are generally congruent with the proposed hypothesis of phylogeny and seem to involve an early Hemingfordian first occurrence in the Great Plains, followed by later Hemingfordian and Barstovian radiations into and within the northern Rocky Mountain region, Oregon, and Nevada. Although this study is limited in scope, it illustrates that with further understanding of ontogenetic changes in occlusal morphologies of ochotonids, cladistic analysis is a viable method for reconstructing ochotonid phylogenies and exploring their biogeography.