Quinn, in Irish Ó Cuinn, comes from the personal name Conn, meaning a person of high intelligence, or, maybe, a freeman. There were a number of distinct families of the same name. In Ulster, where they are most numerous, they were centred in County Tyrone and the Glens of Antrim. There was an important sept that was driven out of County Longford by their kinsmen the O Ferralls of Annaly. In the mid-twelfth century, the O Cuinn of Clann Chuain near Castlebar were a subsidiary of the powerful MacDermotts of Moylurg. The most prominent family was a Dalcassian sept of Thomond in the barony of Inchiquin in County Clare. Place names such as Inchiquin, Ballyquin and Glenquin are spelled with a single n, while in Irish they have a double n. In general Catholics spell their name "Quinn" while Protestants spell it "Quin", but this has never been a rigid rule.Niall O Cuinn, the first of the Dalcassian sept to use the surname, was killed at the battle of Clontarf in 1014. In the thirteenth century, Thomas O Quinn was bishop of the monastery at Clonmacnoise, the famed Irish centre of medieval learning. In the early sixteenth century, during severe religious strife, John Quinn, a Dominican, was Bishop of Limerick.The Quins, whose ancestors were Chiefs of the Clan Hy Ifearnan, gave their name to Inchiquin and also became Earls of Dunraven, and are one of the rare families of true Gaelic origin in the Irish peerage. Thady Quin (born 1645), who settled in Adare, County Limerick, was the ancestor of Valentine Quin who, between 1720 and 1730, built the first Quin manor at Adare by the River Maigue.

He was the grandfather of Valentine Richard Quin (1732 - 1824), 1st Earl of Dunraven. His heir, Windham Henry (1782 - 1850), married an heiress from Wales. Gout prevented him from following the gentlemanly pursuits of fishing and shooting. Instead, with his wife, he rebuilt his home, turning it into a colossal Tudor manor. They built the new house around the existing one, which had to be demolished when the work reached its final stages.Valentine's son, Edwin, 3rd Earl of Dunraven, designed the garden. He was a prominent archæologist. At Eton he showed a strong taste for astronomy; and he afterwards spent three years at the Dublin Observatory under Sir William Hamilton. Natural Science occupied much of his attention; he was also deeply interested in the study of Irish antiquities, and was a prominent member of the Royal Irish Academy, the Celtic Society, and several Archæological associations. His chosen friends were men such as Graves, Stokes, Petrie, Reeves, and Todd.

He accompanied the Comte de Montalembert to Scotland, when engaged upon his Monks of the West, one volume of which is dedicated to Lord Dunraven: "Prænobili viro Edvino Wyndham Quin, Comiti de Dunraven." Attended by a photographer, he visited nearly every barony in Ireland, and nearly every island on its coast. He made his investigations with a view to the publication of an exhaustive work on the architectural remains of Ireland, profusely illustrated with photographs, his main object being to vindicate the artistic and intellectual capabilities of the ancient an mediæval Irish. Having died before the completion of the work, the result of his labours has been given to the world, at the expense of his family - Notes on Irish Architecture, by Edwin, third Earl of Dunraven: Edited, by Margaret Stokes. (London: 1875 and 1877): two superb volumes, with 125 illustrations, most of them large photographs. What may be called the spirit of ancient Irish architecture is brought out in this book in a style never previously attempted in piotorial representations.

When he died in 1871 he was succeeded by Windham, 4th Earl of Dunraven (1841 - 1926), a most remarkable Quin. Privately educated in Rome and Oxford, he was also a fearless steeplechaser and yachtsman. He was a war correspondent in Abyssinia and during the Franco-Prussian war, and afterwards went to Texas to hunt with Buffalo Bill! Unlike some of his predecessors who tended to base themselves in England, his home remained Adare, which he made into the prettiest of villages. He ran a successful racing stud and took an active interest in the affairs of his country. With his yachts Valkyrie II and Valkyrie III he twice failed to win the America's Cup and was denied membership of the club when he disputed the conduct of the races. During the First World War he ran his steam yacht as a hospital ship in the Mediterranean.George Wyndham (1863 - 1913), a relative of the 4th Earl of Dunraven, persuaded the wealthy landlords to accept land purchase and thus made a laudable breakthrough in the centuries-old inequitable ownership of land. This meant that tenants could own their own land, and the Wyndham Land Purchase Act of 1903 is a tribute to his name.Thady Wyndham Quin, 7th Earl of Dunraven (b. 1940), unable to bear the expense of maintaining Adare Manor, sold it and its contents in 1984 for a reputed 2 million. It is now a hotel and golf course.

Thady Quin, who was crippled by polio while a schoolboy, lives with his family in a nearby house.Although the Dunravens predominated for centuries, there were other Quins (and Quinns) of some distinction. Walter Quin (1575 - 1634), a Dublin-born poet, left for London to become a tutor and lifelong friend of Charles I. His son, James Quin (1621 - 59), who was expelled from Oxford for his royalist views, is said to have been reinstated when he charmed the uncharming Cromwell with his "fine singing voice".Quinns served in the armies of James II and, following the collapse of the old Gaelic order, many fled to France. One Quin family settled in Bordeaux, where they are still numerous. They were influential citizens, as demonstrated by a street there called the Rue O Quin.