St Doulagh's Church is the oldest stone-roofed church still in use in Ireland. It is situated approximately 10 kilometres from Dublin city, just north of the hamlet of Balgriffin, within Fingal and in the traditional County Dublin, and is marked as "St Doulagh's Church, Balgriffin". Its complex also comprises an octagonal baptistry built over a holy well - Ireland's only surviving standalone baptistry - and a stone housing over a pool. St Doulagh's is one of the two churches in the Church of Ireland "United Parishes of Malahide, Portmarnock and St Doulagh's.

Balgriffin is a suburb of Dublin, Ireland. It lies on the administrative boundary between Dublin City and the county of Fingal in the traditional County Dublin.