Reilly

The story behind Reilly

Reilly is an Anglicized form of the Irish surname Ó Raghallaigh, derived from the Old Irish personal name Raghallach. The root likely combines "ragh" (related to struggle or striving) with a diminutive suffix. The name evolved through Irish genealogical traditions, where "Ó" denotes "descendant of," making the original form "descendant of Raghallach." As Irish surnames were Anglicized during English colonial rule, particularly from the 17th century onward, Ó Raghallaigh underwent various anglicized spellings including Reilly, Reiley, and Realy. The name became firmly established in English-speaking regions, particularly in Ireland and among Irish diaspora communities in North America. By the 19th and 20th centuries, Reilly had become a common surname throughout the English-speaking world.

The transition of Reilly from exclusively a surname to a given name is a modern phenomenon, gaining particular momentum in the late 20th century. This shift reflects broader trends in English-speaking cultures where surnames are increasingly adopted as first names. Reilly has no specific historical or mythological bearer as a given name, making it a modern coinage in this usage. The name's popularity spike in the 1990s in the United States coincides with this surname-to-given-name conversion trend and the general rise of Irish-origin names among American parents during that decade.