My GGGrandfather Michael Gilligan came to the US in 1848. I'm not sure where he arried at but by 1857 he married Mary Cullen in Dubuque County IA. His parents were on his death certificate as Michael Gilligan and Winefred Kivlehan. I'm not sure where they lived in Ireland. I've been checking in Sligo since I know a Kivlehan who is related to Gilligan but we can't find a for sure connection. I believe Michael had a brother Martin who came about the same time and married a Julia Hopkins. Also a David Gilligan who used the name Michael and lived north of Dubuque in Clayton IA who said he was a relative.
If you have Gilligans and Kivlehans in your family please contact me. My line stayed in Iowa and Martin and David's lines went to Montana to work the mines.