Family History and Genealogy Resources by Surname
Reilly Surname Origin
(Origin Irish) shortened form of O’Reilly, an Anglicized form of Gaelic Ó Raghailligh ‘descendant of Raghailleach’
Source: An Etymological Dictionary of Family and Christian Names With an Essay on their Derivation and Import; Arthur, William, M.A.; New York, NY: Sheldon, Blake, Bleeker & CO., 1857.
Reilly Surname Meaning and Family Facts
There is more to Reilly family history than the origin of your surname:
A Reilly Family History Thought:
'I don't have to look up my family tree, because I know that I'm the sap.' --Fred Allen