I know this is a dated post, but I just came across it. My great grandfather was one Thomas J. Hamill, born May, 1852. Both New York and Ireland are listed as his places of birth. He married a woman named Ellen Hanley in 1880. There is a census record from 1880 listing Thomas and Ellen Hamil, married that year. They had children named Mary, Bernard, Eleanor(aka Ellen, aka Loretta, aka Lauretta),Michael, Peter and Thomas, Jr. My Thomas died in the Bronx in 1905 from pneumonia. None of the sons ever married. Loretta was my grandmother. There was a Patrick Hamill that lived in brooklyn on Claremont Ave that they would visit often. My mother only knew them as Mr. and Mrs. Hamill. Patrick's children had names almost identical to Thomas's kids. Patrick owned an Auto parts store. Thomas's death certificate lists his parents as Henry Hamill and Mary Duffy. I too am stumped as to where he was truly born. Hope your trip to ireland went well.