This paper explores how geophysical survey, undertaken in conjunction with landscape and historical analysis, is contributing to a deeper understanding of prehistoric focal centres and landscape organisation in the wider ‘hinterland’ of the Hill of Tara, Co. Meath. Arising out of the Discovery Programme’s ‘Late Iron Age and ‘Roman’ Ireland’ (LIARI) Project, the present investigations targeted a number of prominent hilltop sites in the Meath–north Dublin region suspected, on the basis of archaeological, topographical, and early documentary evidence, to have been important ceremonial/political centres in later prehistory. Foremost among these are the Hill of Lloyd (Co. Meath), the location of a prehistoric enclosure overlooking the early monastic foundation at Kells; Faughan Hill (Co. Meath), the traditional burial place of Niall of the Nine Hostages; and Knockbrack (Co. Dublin), whose summit is crowned by a large, internally-ditched enclosure with central burial mound. The discovery through this multi-disciplinary study of additional large-scale enclosures, burial monuments, and other significant archaeological features serves to further corroborate the deep historical importance of these sites, and opens up new avenues for exploring such themes as territoriality, social organisation, and identity in the wider Tara region.