O'Regan family genealogy
Arms: Az. an eagle disp. ar.
DUBHREAN, a younger brother of Dun who is No. 104 on the "O'Dunn" pedigree, was the ancestor of O'Riaghain (one of the "Four Tribes of Tara"); anglicised O'Regan.
104. Dubhrean: son of Dubhghall.
105. Dubhda: his son.
106. Maolcroine: his son.
107. Giollamuire Caoch O'Riaghain ("riagh:" Irish, to gibbet): his son; Chief of Hy-Riaghain—now the barony of "Tinehinch," in the Queen's County.