Based on the findings of more than 10 years of regional archaeological survey, the prehispanic settlement history of the Valley of Oaxaca in Southern Mexico is presented for the 3,000-year period prior to Spanish Conquest. The process of long-term demographic change is examined at several analytical scales and discussed in relation to political and economic transitions. Specific emphasis is given to the discussion of those parts of the Valley that have been surveyed most recently and the new information and interpretations that have been generated by this work.