Portal tombs, of which there are approximately 180 in Ireland, are the least studied of the great megaliths of Neolithic Ireland. Three aspects are specifically focussed on in the present study: landscape siting of the portal tombs, portal tomb morphology, and evidence for ritual in the construction and use of portal tombs.Portal tombs, of which there are approximately 180 in Ireland, are the least studied of the great megaliths of Neolithic Ireland. Three aspects are specifically focussed on in the present study: landscape siting of the portal tombs, portal tomb morphology, and evidence for ritual in the construction and use of portal tombs.