Recorded in various spellings including Brannan, Brannon, Brannen and Brennan, this is a complex surname of Irish origins. It derives from either of two distinct Gaelic surnames originally O'Braonain and Mac Branan. The prefix o' indicated a male descendant of, whilst "braon", was a personal or baptismal name which may have translated as "sorrow". The name as MacBranan translates as "the son of Bran", with Bran meaning raven, and hence a nickname for somebody who was alledged by his compratriots to have the aptitudes of this often ferocious bird! Most original Gaelic clan and family names originated from a nickname for the first chief, and this would seem to be no exception. The diminutive suffix "-a(i)n" is attached to both names. The Brannon (O'Braonain) sept belonged to the province of Leinster where prior to the 17th century, they held considerable estates in the ancient kingdom of Osraighe (now County Kilkenny). It seems that in later years several clan members became prominent highwaymen! The MacBranans belonged to County Roscommon and their chiefs held sway there from 1159 to 1488. Early examples of the surname recordings include Patrick Brannon, the son of John Brannon and Margret McGrath born at Boyle, County Roscommon on May 28th 1866, although much earlier Tead MacBranain, shown as the chief appears in the Annals of the Four Masters, during the reign of the High Kings of Ireland, 1022 - 1166. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.