I recently found out that it was my Irish ancestors who were my first ancestors to come to America. My great-great-great-great grandparents: Bernard McLaughlin and Mary Delahenty were born in 1799 and 1798 respectively in Ireland. I'm not sure exactly when they arrived in America, but I do know that they settled in Maine and that my great-great-great grandfather Bernard Barney McLaughlin was born in Maine in 1834. Bernard Barney, an Irish American, married an Irish immigrant named Susan Melhern and had my great-great grandfather William McLaughlin, who married a woman named Maud Martin from New Brunswick. I'm not sure what kind of last name Martin is. Is it Irish? According to this site there is a large population of Martins in Ireland, so who knows.
So I'm at least 1/16 Irish. If Maud Martin is of Irish decent, then I'd be 1/8. Even so, it's not a whole lot, but I enjoyed learning about my first ancestors in America. I'm really surprised I got back that far.