Under the Public Records Act 1867, an amendment of 1875 and the Parochial Records Act 1876, Church of Ireland parish registers of marriages prior to 1845 and of baptisms and burials prior to 1871 were declared to be public records. However, registers could be retained in parochial custody if an adequate place of storage was available. The registers of all but four of the 1,006 parishes deposited in the Public Record Office of Ireland were destroyed in 1922. The registers of 637 parishes in local custody fortuitously survived, and in addition transcripts of or extracts from destroyed registers are available in the case of some other parishes.

While repealing the Acts of 1875 and 1876, the National Archives Act 1986 effectively confirmed the status of Church of Ireland Parish Registers as public records. The National Archives is in the process of completing the making of microfilm copies of surviving Church of Ireland parish registers, but not all of these are yet accessible to the public (see card index of available copies). The Public Record Office of Northern Ireland in Belfast holds microfilm copies of nearly all surviving registers for the Six Counties. A growing number of surviving original registers is in the Representative Church Body Library in Dublin, while others remain in local parochial custody.