Recorded in several spellings including O' Culligan, O' Quilligan, Qulligan, Culligan, McColgan, Colgan, and probably others, this is an Isrish surame. It originates from the pre 10th century Gaelic O' Cuilleagain, which means the descendant of Colgan, a name deriving from "coll", meaning a hazel tree. Quilligan, and the other variant spellings are County Clare names, as well as in the city of Limerick part of which lies on the Clare side of the Shannon. In the 19th century Culligan was much more numerous than Quilligan, but more recently they are about equal. It is thought that originally the sept was from County Offaly, migrating westwards in the 16th Century, to West Clare where they were well established by the 17th Century. Cullegane is returned in "Petty's Census" as a principle name in the barony of Clonderlaw. One Ellen Quilligan married William Henry Lincoln on August 27th 1822 at St. James, Paddington, London. On April 26th 1847 Mary Quilligan, aged 13 yrs., embarked from Limerick on the ship "Annamaria" bound for New York. She was one of the several thousand famine immigrants to enter the city that year. The first recorded spelling of the family name is shown to be that of Bartholomew Quiligan, (as spelt), witness at the christening of his daughter, Ellen, which was dated August 10th 1794, Roman Catholic Church, Killarney, Co. Kerry, during the reign of King George 111, "Farmer George", 1760 - 1820. 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.