All births, marriages and deaths occurring since 1 January 1864 (and Jewish and non-Roman Catholic marriages occurring since 1 April 1845) should be on record in the General Register Office, Werburgh Street, Dublin 2. All written communication for the General Register Office should be addressed to the General Register Office, Government Offices, Convent Road, Roscommon.
For the six counties which comprise Northern Ireland (Antrim, Armagh, Down, Fermanagh, Londonderry/Derry and Tyrone) from 1922 onwards, records of births, marriages and deaths should be held by General Register Office Northern Ireland, Oxford House, 49-55 Chichester Street, Belfast BT1 4HL. This General Register Office also holds all local register books for Northern Ireland from 1864 (for births and deaths) and from 1922 (for marriages).
A database of the civil registration indexes is free to search on FamilySearch for the period 1845-1958 (all of Ireland is covered from 1845 until 1922 and the Republic of Ireland from 1922 onwards). For a comprehensive guide on civil registration, researchers should consult Eileen Ó Dúill and Steven C ffeary-Smyrl’s Irish Civil Registration – where do I start ? (Council of Irish Genealogical Organisations, Dublin, 2000).