The research reported in this monograph evaluates the role of the Moctezuma Valley of eastern Sonora, Mexico in pan-regional connections between the U.S. Southwest and Mesoamerica (central Mexico). Previous work interpreted the area as an important conduit of goods and ideas between these two regions. This research, however, indicates great variation likely existed in the Sierra Madre communities of eastern Sonora. Data from the Moctezuma Valley and a re-evaluation of previous research now suggests only small scales of social integration are indicated by population distributions and shared styles of material culture. Overall communities of the Sierra Madre appear balkanized with different political, social, and perhaps even ideaological affiliations characterizing neighboring communities.