In this presentation, local archaeologist Michael Kellett, M.A., will present his research on prehistoric obsidian acquisition in the Northern and Southern Sinagua, Prescott, and Cohonina culture areas. Kellett will share the plausible foraging and exchange routes he has mapped through analyzing obsidian artifacts at 608 prehistoric sites in west-central Arizona using a portable x-ray fluorescence (XRF) spectrometer. He will explain how he has inferred these routes based on the spatial distribution of obsidian artifacts and least-cost path modeling that integrates slope, proximity to water, and vegetation community type.