O'Reilly - Irish Surname Origin & Meaning
Irish form: Ó Raghallaigh
Meaning: “sociable / gregarious”
Traditional stronghold: Cavan
Pronunciation: oh-RY-lee; Irish O Raghallaigh: oh RY-lee
History of the O'Reilly name
The O'Reillys were the dominant sept of east Breifne, the territory now largely corresponding to County Cavan, where they ruled as chieftains from the 14th century and issued their own coinage, the 'reilly'. Descended from Raghallach, a Connacht prince, the family split into several branches contesting the chieftaincy over the centuries, and Cavan remains the traditional heartland of the name to this day. Following the Elizabethan conquest and Ulster Plantation many O'Reillys served as soldiers on the continent, and the name spread through the Wild Geese to Spain, Austria and France. It is now among the most numerous surnames in Ireland, especially concentrated in Cavan, Meath and Longford.
Variants: Reilly · Riley · O'Rielly
Famous bearers of the name
- Alexander O'Reilly - Spanish general of Irish origin, colonial governor of Louisiana
- Bill O'Reilly - American television host and author
- Emily O'Reilly - Irish journalist and European Ombudsman
- Miles O'Reilly - 19th-century Cavan-born poet and satirist
Related names from the same part of Ireland: Brady · McGowan · Smith · Clarke · McCabe · Dolan · Sheridan · McGovern