Find Ancestors

I am trying to find any info.about my great granfather Patrick Corrigan. He was born in Ireland,possibly Cork in 1851.His wife was Ann and they had sons Thomas,James,Patrick,daughters Mary(Polly) Cecilia, Hannah. They are listed in 1891, and 1901 census as resident in Bolton, where I'm originally from.In the 1871 census I have found a Patrick Corrigan living in Much Woolton, Prescot. His birth was in Ireland, his age is spot on. He was 20 then. His father was Thomas (45) born Ireland,wife Ellen(39)born Ireland,son James(25) Ireland,son Patrick(20) Ireland,reference to blindness,but only that once.Then William(16),John(12), and Ellen(10)-the latter 3 born in Much Woolton.There is a reference to patrick aged 10 in 1861 census,born Ireland, but from what I can make out, though everything else seems to be fairly accurate, the head of house lives next door to the family, and has a squiggle of a name that looks like terrence, not Thomas. I think they came across in the Famine, but I would be grateful to any one who knows of any of these. My dad is 80, was the only child after 27 years of marriage and has alays longed to find out his mum's (Mary Agnes Corrigan's/Polly's routes in Ireland. I hope you can help and thanks for reading my 'essay!'