Ó Conghalaigh is a Gaelic Irish surname, most widely known in its anglicized form Connolly. The name derives from the Irish Ó Conghalaigh, meaning "descendant of Conghalach." Conghalach itself is a personal name derived from conghal, traditionally interpreted as "fierce as a hound" (from cú "hound" and gal "valor").Historical BackgroundIn historical Gaelic Ireland, several unrelated clans or families bore the surname Ó Conghalaigh, each with distinct origins and territories. These included:Ó Conghalaigh of Iar Connacht (now County Galway)Ó Coingheallaigh in the Kingdom of Desmond (now west County Cork)Ó Conghalaigh of Derrygonnelly, County FermanaghÓ Conghalaigh of Airgíalla (covering parts of County Monaghan and County Meath)Ó Conghaile Muirthemne from County LouthThe multiplicity of distinct families has contributed to the surname's widespread distribution throughout Ireland.Anglicization and VariantsThe surname has been anglicized in various forms, including Connolly, Connelly, and sometimes Conley. In modern Irish, it is also spelled Ó Conghaile. The numerous spelling variants reflect the different regions where the families settled, as well as the lack of standardized orthography during the period of anglicization.Modern DistributionIn 1890, Ó Conghalaigh/Connolly was the twenty-third most common surname in Ireland, with 381 births registered under the name, predominantly in the province of Ulster. By 1996, its ranking had slipped to thirty-third place, reflecting demographic shifts and emigration patterns, though it remains a widely encountered family name across Ireland.Key FactsMeaning: Descendant of Conghalach (“fierce as a hound”)Origin: Gaelic IrishType: Patronymic surnameAnglicized forms: Connolly, Connelly, ConleyPrimary usage region: Ireland (historically widespread, especially in Ulster)