This is an anglicized form of an Olde Gaelic name O Finn. The Gaelic prefix 'O' means 'grandson' or 'male descendant (of)' and the personal name , Finn, coming from 'fionn' meaning 'fair (haired)'. There were three main O'Finn clans in Ireland. The first belonged to Co. Sligo where their chiefs held sway over the lands of Calry on the shore of Laigh Gill. The Co. Sligo place name, Coolavin (in Irish Cuil O bhFinn) means 'the refuge place of the O'Finns'. A second sept held church lands and property in Kilcolgan, Co. Galway and the third sept belonged to the ancient territory of Oriel (Co.s Armagh and Monaghan). They spelt their name MacFhinn or Maginn. Petty's 1659 census shows the name Finn to be widespread in Co. Cork. The first recorded spelling of the family name is shown to be that of O'Finn, Bishop of Munster which was dated 1020 in the Annals of Inis Faithleann during the reign of Malachy 11, High King of Ireland 1014-1122 Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.