Ó Ruadhagáin
Ó RUADHAGÁIN—I—O Rogane, Rogan; 'descendant of Ruadhagán' (a diminutive of ruadh, red); also written Ó Ruadhacháin, which see; the name of an Oriel family who were chiefs of Ui Eathach, or Tuath Eathach, a district embracing the present barony of Armagh; common in Ulster and Connacht.
Alphabetical Index to Irish Surnames