This surname was adopted by several distinct septs:

A sept of the Cineál Eoghain who established themselves in Clanndeboy in the present Antrim during the fourteenth century.

A sept of the Cineál Eoghain in Magh Itha, now comprised in the barony of North Raphoe in Donegal. O’Duggan writing in the early part of the fourteenth century referred to :

In the 1850’s there were 176 Quinn households in Donegal; the largest concentration being in the parish of Donaghmore (35); followed by the parish of Inishkeel (23).

My great-grandfather William Quin a scutcher of flax lived in Gobnascale, and his father Daniel died in nearby Callan.

A sept of the Cineál Eoghain, who inhabited that part of Tír Eoghain, in the barony of Loughshilon now in County Derry.

A sept who were chiefs of Magh Lughadh and Síol Chathasaigh in Antrim.

A sept of Thuas Mhumhan (Thomond), also found in Tipperary a branch of the Dál gCais, descended from Conn, lords of Muintir Iferainn, originally seated at Inchiquin.

A sept of Anghaile (Annaly), a branch of the Conmhaicne and of the same stock as ó Fearghail (O’Farrells), who were chiefs of Muintir Ghiollagáin, an extensive district in Longford until they were displaced by the ó Fearghail.

A sept known as the Clan Chuain of Uí Fiachrach (Sligo and north Mayo). During the twelfth century they transferred their allegiance to Mac Diarmada (MacDermott) of Moylurg.

A sept of Uí Fiachrach,who were chiefs of Cúil Chearnadha.

A sept of Tír Amhalgaidh, now the barony of Tirawley in Mayo, who were Chiefs of Dun Fine, now Dunfeeny, nine miles north-west of Killalla. A sept of the race of Laeghaire, of the same stock as the ó Moráin (O’Moran) who were chiefs of an area around Ballycong, near Ballymore Lough in the parish of Attymas, in the barony of Gallen.

At the close of the fourteenth century an O’Neill took the name Quinn and his descendants settled in Galway.

The surname has been in Dublin for the past four hundred years and amongst its bearers have been a tutor to the Scottish royal family, a Lord Mayor and a famous actor.

The surname has been in County Wicklow since at least the seventeenth century and in 1854 there were 53 Quinn households.

Quinn was the nineteenth most numerous surname in 1890, the estimated number of bearers was 18,200, and it was the most numerous surname in Tyrone. In that year the name was to be found in every county in Ireland. It was principally to be found in Dublin, Tyrone, Antrim, Roscommon and Galway.

In the United States, Quinn is the 402nd most numerous surname with an estimated 77,000 bearers, O’Quinn is the 6,426th most numerous surname with an estimated 5,500 bearers, and Quin is the 15,374th most numerous surname with an estimated 2,500 bearers. This gives an estimated total figure of 85,000 for Quinn including variants. It is numerous in the states of Connecticut, New Jersey, and New York.

In England and Wales in 1996 it was the 255th most numerous surname.