I have been reading about the The Troubles in Northern Ireland but have been curious about all those who would have been displaced by the violence (refugees and those who chose to migrate to avoid the violence).
An fair few refugees from Northern Ireland ended up in the Republic (typically Catholics for obvious reasons). One famous example would be the 8th President of Ireland, Mary McAleese who was born in Belfast, but whose family had been driven out by a Unionist mob during the early phase of the Troubles and resettled in the south.
In 1970, there were about 1,500 refugees from the North; in mid-July 1971, just after the annual 12th July Celebrations commemorating the Battle of the Boyne, there were more than 5,000. The Irish government at the time appears to have held some suspicion that many of the refugees had not been burnt out of their homes, but were instead visiting Ireland for a few weeks' peace and quiet.
Diarmaid Ferriter, Ambiguous Republic: Ireland in the 1970s (London, 2012).