The co-occurrence of matrilocality and maize-based agriculture among historical northern Iroquoian groups of New York and southern Ontario has long been of interest to anthropologists and archaeologists. The traditional explanation of this association is that gradual evolution of maize-based agriculture through female labor enhanced female status in families, which resulted in matrilocality. Dean Snow (1995a) recently challenged this in situ hypothesis of matrilocality by arguing that the sudden appearance of maize-based agriculture and matrilocality can only be explained by the migration of ancestral Iroquoian agriculturists into areas already inhabited by other people. Matrilocality arose because it allowed a focus on external warfare by men against the hostile original inhabitants. In contrast, and based on a general model of maize agriculture evolution and the effects of postmarital residence patterns on that model, I argue that neither in situ development hypothesis nor Snow’s migration hypothesis affect the coevolution of matrilocality and maize agriculture, and that their “sudden” appearance cannot be used as evidence in support of either hypothesis. I also show that current archaeological evidence for maize agriculture and matrilocality support a gradual coevolution of maize agriculture and matrilocality rather than the sudden appearance argued by Snow.