I'm so happy to have found this thread! I don't have much time to do much poking around just now as I am off tomorrow for two weeks in Ireland (my first trip there)! I wanted to let you know that we have a John O'Halloran, born circa 1800 in Feakle, County Clare. He was married in Feakle in 1825 to a (Mary) Ann Maroney (sp?). They had four children: John (married in Ireland; his first wife died, leaving one son: Patrick; John married a second time and also had children by that marriage, but we have no other details).
The second son of John and Ann (Maroney) O'Halloran was Patrick. He died in Ireland in approximately 1915 and also had several children. Two of them settled in Bethlehem, Pennsylvania: Margaret married a William McNamara and her sister Katherine married a Joe Ackerman.
The third son was Thomas. He came to the US in 1866 and settled in San Rafael, CA, soon after his marriage to a Maria Naylon (sp?). They had three children: Ann, Michael and Belle.
The fourth son (my great-grandfather) was Michael O'Halloran. Michael was born "in a log row" in Cloonagro, County Clare, on September 1, 1844. Michael came to the US in 1866 with his brother Thomas. On January 23, 1870, he married Mary Connors (or O'Connor) formerly of Kilrush, County Clare, and they had the following children: John, Thomas, Martin, Anna (my grandmother), Sara, Michael and Charles.
I do have some more information on this family, but this is all I have pertinent to the Feakle area or County Clare in general. I would love to know if you have any information on the Hallorans who remained in County Clare.