The genus Castor is represented in Eurasia by Castor fiber, North America by C. canadensis, and has been in North America since the late Miocene. This study aims to assess whether morphology of Miocene-Pliocene C. californicus and extant C. canadensis are distinctly different. Specimens of Castor were compared using geometric morphometrics on cranial material and linear measurements of postcranial material. Species occurrence data were compared with past and future climate data to assess Castor distribution in North America through time. Results show that C. canadensis is highly variable in both cranial and postcranial morphology and C. californicus falls largely within the range of variation seen within the extant species. Past distributions match fossil occurrences of Castor, suggesting confidence in projected models. Morphological and distribution similarities between the two species suggest that they can be treated as ecological analogs, though evaluation of whether they are conspecific will require more data.