Hillforts represent the largest and arguably most impressive archaeological monuments in the Irish landscape. While the study of hillforts progressed rapidly in Britain during the twentieth century, it was not until the work of Barry Raftery in the late 1960s and 70s that these great enclosures became the focus of sustained research in Ireland. Raftery’s excavations at Rathgall in Co. Wicklow became the cornerstone of Irish hillfort studies, and began to reveal a different history of design and use from that recorded in Britain. Whereas hillforts in Britain and the Continent are more generally associated with Iron Age societies, their Irish counterparts have close connections with warrior societies of the later Bronze Age. As in Britain, recent research has highlighted the phenomenon of Neolithic hillforts in Ireland, and the possibility that some sites of the early medieval period should be considered in this way. This chapter discusses the developing narrative of hillfort studies in Ireland, and considers how the Irish examples compare with their British counterparts as recorded in the new Atlas of Hillforts of Britain and Ireland..