The key to finding information on Irish relatives is the location (civil parish if not the actual townland not just a county or 'Ireland') and their religion.
I'm in that boat. For years I was told that Grandfather was born in Ireland. Turned out HE was born in Liverpool but it was HIS father who had been born in Ireland.
So I have CHRISTOPHER McGURN born c1814 Leitrim married to MARY GORMLY born c1820 Roscommon. They are both on the 1841 census so obviously came to Liverpool before the potato famine.
Did find out from Christophers sister (in 1841/1851 census records) marriage in 1851 that their fathers name was PHILIP.
So the question are:
1. How do I find out which Townland/Parish they came from?
2. Were they of different religions?
3. Two different Irish Counties so how did they meet and then marry?
Names Christopher and Philip seem to be Protestant names (Catholics usually have Cornelius and Patrick) plus family folklore is that they came over because of being the black sheep of the family (although this was thought to refer to work and not religion)
Biggest problem I can see is the surname. How would it have been spelt in Ireland. I know from certificates I have of their children plus two entries on census records that the name has been spelt McGarvey, McGorrin, McGwidle just to name three variants.
Still I suppose having this brickwall keeps me out of mischief

Jean