Erin go Bragh /ˌɛrɪn ɡə ˈbrɑː/, sometimes Erin go Braugh, is the anglicisation of an Irish language phrase, Éirinn go Brách, and is used to express allegiance to Ireland. It is most often translated as "Ireland Forever."
Erin go Bragh is an English corruption of the phrase Éirinn go Brách in the Irish language.
The standardised spelling in Irish is Éire go Brách, which is pronounced [ˈeːrʲə ɡə brɑːx]. However, Éirinn (which survives as the dative form in the modern standard) is a historic form used instead of Éire in two dialects; this is the source of the anglicised Erin. In all other dialects the distinction between the nominative-accusative Éire and the dative Éirinn is kept distinct. This linguistic shift (dative forms replacing nominative) is common among Irish nouns of the second and fifth declensions.
The term brách is equivalent to "eternity" or "end of time", meaning the phrase may be translated literally as "Ireland until eternity" or "Ireland until the end (of time)". Éire go Bráth (or Éirinn go Bráth) is also used in Irish and means the same thing. Go is a preposition, translatable as to, till/until, up to.
In time, the phrase became anglicised. By 1847, it was already in use as "Erin Go Bragh". That year, a group of Irish volunteers, including U.S. Army deserters, joined the Mexican side in the Mexican–American War. These soldiers, known as Los San Patricios or Saint Patrick's Battalion, flew as their standard a green flag with a harp on it, with the motto "Erin Go Bragh" underneath. Variations on this flag design have been used at different times to express Irish nationalism.