The separation between anthropology and geography is a factor of time, and the divergent meanderings of disciplinary histories. As Larry Grossman once argued, “Cultural geographers and anthropologists are like brothers separated in infancy and taught to speak different languages” (1977:126). In many ways, this is quite true. Anthropology and geography actually do share many roots and intellectual origins, even if these connections aren't exactly emphasized in the respective disciplinary histories. Interestingly, if there is one crucial common ancestor that American geographers and anthropologists share, it is none other than one of the icons of North American anthropology: Franz Boas.
Anderson, Ryan B., "Franz Boas: Geographer/Anthropologist" (2011). Faculty Publications. 64.