From the longer Wikipedia page 
The National Archives of Ireland (Irish: Cartlann Náisiúnta na hÉireann) is the official repository for the state records of Ireland. Established by the National Archives Act 1986, it came into existence in 1988, taking over the functions of the State Paper Office and the Public Record Office of Ireland. The National Archives moved to its current premises in Bishop Street, Dublin, in 1991. The Archives stand on the site of the Jacob's Factory, one of the garrisons held by rebels during the 1916 Easter Rising.
The State Paper Office (founded 1702) was originally based in Dublin Castle. The Public Record Office of Ireland was established under the Public Records (Ireland) Act, 1867 to acquire administrative, court and probate records over twenty years old. During the Civil War, the Four Courts, where it was based, was seized and the repository building destroyed by detonating explosives and fire in June 1922, along with most of the records, some dating back to the thirteenth century.
When the southern part of Ireland became independent as the Irish Free State in 1922, the Public Record Office of Northern Ireland was set up to take over the records of that part of Ireland which remained in the United Kingdom.
The website is