Finn, together with the rarer O'Finn, comes from O Finn, from the Irish fionn, meaning "fair" or "fair-haired". From the medieval Annals, the name appears to have arisen independently in at least three distinct areas, in the north Lenister kingdom of Oriel, in Co. Galway and in Co. Sligo. The Leinster family seem to have died out early on; at any rate little is heard of them after the middle ages. The Galway family were based around Kilcolgan in the south of the county, where they were hereditary abbots of Kilcolgan. In Sligo, the O'Finns were the pre-eminent family of the area of the parish of Calry, near the modern town of Sligo.
Edmund Finn (1767-1810) is well remembered as a member of the United Irishmen, prominent in the rising of 1798. Exiled after the failure of the rising, he served with the army of France.