Ó Céileachair
Ó CÉILEACHAIR—O Keallaghir, O'Kelliher, Kellegher, Kelleher, Kelliher, Keller, &c.; 'descendant of Céileachar' (companion-dear, spouse-loving); the name of a well-known family in Cork and Kerry. They are of Dalcassian origin, being descended from Donnchuan, brother of Brian Boru.
Alphabetical Index to Irish Surnames