One source said that they came to America and went back and forth. My first four generations all came over after Samuel Irwin and his 4oldest children . I only have one more of his children because Christoper Irwin was my direct line and he did not come over until later but I do not know the exact date of when any of them came over . Could never find any other children of Samuel nor his spouse who I think may have been a Duncan. Do know that all children of 3rd. generation were born in Ireland but married and died in York Co.Pa. Have found that the part of Lancaster Co.where the Irwin's lived was later part of York Co.I have contacted them and they are wonderful in York Co. Was able to get a lot of wills etc. from there.I don't have Patrick or Julianna but since I had to pay a researcher to get some information and she said that the Irwin's that came from Delware and came up to Lancaster Co. were not related to me.Don't mean that they could be related , just didn't have them on my family tree that was given my family. There are lot of errors on the history of the Irwin's in Pa.They got Christopher Irwin the second generation all messed up with the 4th generation Christopher who came to Ohio when he was 15 years old . Still have never found a spouse for him . AT least nto Joseph my GGG Grandfther who married in Athens Co. Ohio . He was born in Ohio but have never found where. Know were he is buried in Athens Ohio. HIs brother who was two years younger lived with Christopher when he was 39 in Huron Co. Ohio . Christopher had 2nd wife Elizabeth Price and 3rd Nancy Hartness.