ABSTRACT Appreciating variation along the edges of traditional archaeological Culture Historical boundaries requires close consideration of social contexts associated with culture contact. We focus on dietary variation as a function of these concerns through a case study of Fort Ancient populations who, on average, consumed lower quantities of maize than their Mississippian neighbors as determined by stable carbon isotope ratios of bone collagen. However, this dichotomy is not as rigid as initially thought, with some Fort Ancient burials producing stable carbon isotope ratios similar to Mississippian cases. Detailed investigation of internal variation of carbon isotopes for human burials at the SunWatch site provides evidence that contact included small-scale Mississippian migrations to Fort Ancient sites. The main conclusion is that variation in diet and archaeological context can be a useful approach for examining prehistoric migration.