GUILFOYLE Family History
Recorded in several forms including MacGilfoyle, Gilfoyle, Guilfoyle, and Kilfoyle, this is an Irish surname. It originates from the pre 10th century Gaelic name Mac Gilla Phoil, meaning "The son of the follower of St. Paul". It is said that some nameholders in Ireland called Powell derive from the same source, but this is difficult to quantify as the English and Welsh surname Powell is also well recorded in Ireland. The clan were once the chiefs of Kings County, which since the establishment of the Republic has been renamed Offaly.