At the turn of the twenty-first century, critics suggested that warfare profoundly shaped cultural change in the prehistoric Southwest/Northwest. This challenge was part of a much larger debate concerning violence and warfare before civilization. It has become clear that scholars need to consider violence and warfare to understand the aboriginal history of the Southwest/ Northwest. Increasingly, archaeologists are asking: How did indigenous peoples practice war? How did warfare relate to social organization, adaptation, and religion? How did these relations change over time? Many authors have argued that we best answer these questions in well researched and carefully considered case studies. In Sonora, México, prehispanic peoples constructed terraces on isolated volcanic hills and built rooms, compounds, and other edifices on their summits to create cerros de trincheras. The Cerros de Trincheras and Defense Project mapped and collected Trincheras Tradition cerros de trincheras in Sonora. We used Geographic Information Systems analysis to demonstrate how these cerros de trincheras were defensive, what defenses protected, and how these relationships changed over time. This article compares Trincheras Tradition cerros de trincheras to general models of “primitive “ war, Yuman warfare, Andean Colla pukaras, and New Zealand Maori pas in order to infer a Trinchereño way of war.