A number of research projects on migration flows between Scotland and Ireland during the Plantation era have been conducted by social and religious historians. By providing an examination of the diffusion of Presbyterianism across the Irish Sea, this thesis addresses some of the dearth of work on cultural diffusion during the Plantation by geographers. To accomplish this goal, the thesis asked seven questions. In answering these questions, a dissenting Irish Sea culture area is described. The economic and political contexts in which the Plantation occurred are also delineated. The thesis then provides empirical analyses on the social and institutional networking patterns of the ministers who served in Irish Presbyterian churches. The last two empirical chapters concentrate on questions about deposition patterns and the trans-Channel nature of seventeenth-century Scottish geotheology. The final chapter provides a summary of the findings.