Ó Céileacháin
Ó CÉILEACHÁIN—I—O Kellechan, O Kellichan, Kelaghan, Keleghan, Kellaghan, Keelaghan, Kelihan, (O'Callaghan, Callaghan), &c.; 'descendant of Céileachán' (diminutive of Céile); the name of an Armagh family who were anciently chiefs of Ui Breasail; to be distinguished from Ó Ceallacháin, which see.
Alphabetical Index to Irish Surnames