I believe I have your ancestor, John O'Brien in my famiy tree. He was baptised 15 May 1842. He had a twin brother, Christopher. His parents are James O'Brien and Susan Gleeson of Shandrum, Mullagh, County Clare, Ireland.
Please contact me at firstname.lastname@example.org
I have contacted to your tree with mine.
Kevin J. O'Brien, Buffalo, New YOrk