O'Reilly

This article is about the surname. For other uses, see O'Reilly (disambiguation).

O'Reilly
Ó Raghallaigh
O'Reilly arms
Parent houseUí Briúin Bréifne
CountryKingdom of Connacht
FounderRagheallach mac Cathalan
Final rulerMaelmordha O'Reilly
Titles
  • King of East Bréifne
  • King of Muintir Maelmórdha
  • Conde de O'Reilly
Dissolution1602
Cadet branchesBrady
Vesey
A defaced O'Reilly crest adorns the coat of arms of County Cavan, their historic patrimony

O'Reilly (Irish: Ó Raghallaigh)[1] is a common Irish surname. The O'Reillys were historically the kings of East Bréifne in what is today County Cavan. The clan were part of the Connachta's Uí Briúin Bréifne kindred and were closely related to the Ó Ruairc (O'Rourkes) of West Bréifne. O'Reilly is ranked tenth in the top twenty list of most common Irish surnames.[citation needed] It is also the patronymic form of the Irish name Reilly (Irish: Raghallach).[2] The name is commonly found throughout Ireland, with the greatest concentration of the surname found in County Cavan followed by Longford, Meath, Westmeath, Fermanagh and Monaghan, and the Province of Leinster.[citation needed]

  1. ^ "Raghallach — Database of Irish-language Surnames". Gaois. Retrieved 26 December 2022.
  2. ^ "Ó Raghailligh - Irish Names and Surnames". www.libraryireland.com. Retrieved 26 December 2022.