 City status in Ireland is decided by legislative or royal charter . Dublin , with over 1 million residents in the Greater Dublin Area , is the largest city on the island . Belfast , with <unk> @,@ <unk> residents , is the largest city in Northern Ireland . City status does not directly <unk> with population size . For example , Armagh , with 14 @,@ 590 is the seat of the Church of Ireland and the Roman Catholic <unk> of All Ireland and was re @-@ granted city status by Queen Elizabeth II in 1994 ( having lost that status in local government reforms of 1840 ) . In the Republic of Ireland , Kilkenny , seat of the Butler dynasty , while no longer a city for administrative purposes ( since the 2001 Local Government Act ) , is entitled by law to continue to use the description . 
