As part of efforts to improve water management in Ireland there is a need to promote greater awareness of groundwater issues amongst the general population. One means by which hydrogeologists can engage and educate local communities about groundwater issues is by addressing topics of direct interest to them, such as holy wells. In Ireland there are more than 3,000 holy wells, many of which are sites of devotion, especially on the pattern or saint’s day. Some of these holy wells are visited by pilgrims seeking a particular cure for an ailment (eye cures, backache, toothache are common examples). Many have been associated with a more generic power of healing and wellbeing. Whilst Irish holy wells have been the subject of scholarly study in disciplines such as archaeology, history, geography and cultural studies, very little attention has been given to their hydrogeological settings. This paper describes the results of a hydrogeological characterisation of Irish holy wells, based on a GIS analysis supplemented by field surveys of more than 200 wells. It was found that holy wells occur in most types of geology in Ireland, and are common in the less productive as well as in the regionally important aquifers. Importantly, however, they occur more frequently in areas classed as having extreme or high groundwater vulnerability to pollution; this is consistent with the observation that many holy wells are in fact springs or shallow wells constructed around springs or groundwater seepages. Many holy wells have been lost through neglect or through various development projects, and there is a need to preserve important wells as part of our geological as well as our cultural heritage. The current high levels of interest in holy wells amongst certain communities may warrant a move towards some more formal protection of these wells as a community resource.