Reconstructing Late Prehistoric exchange patterns in San Diego County will be a complex task, requiring prehistorians to disentangle the movements of resource materials, finished products, and people. Lithic, ceramic, faunal, and floral archaeological remains offer various possibilities. Of these, the evidence form lithic tools and wastes is most readily usable at present. An analysis of archaeological material from the Corral Canyon Prehistoric Archaeological District (Cleveland National Forest), in conjunction with data from other areas of inland San Diego County, suggests that western Kumeyaay-Diegueño individuals and groups moved relatively freely between the Pacific Coast and the crest of the peninsular mountain ranges, unhindered by kin-group territoriality. It is also suggested that the primary material for flaked lithic artifacts, volcanic or metavolcanic rock, was directly procured in areas outside the range of daily foraging based at Corral Canyon. On the other hand, formal exchange, rather than individual transhumant procurement, is suggested for obsidian, the exchange of which may have played an important role in inter-group relations during the fall acorn harvest in the upper mountains.