Where did the Gillilands come from? "Surnames of Scotland" by George F. Black states that Gilland, Gilliland, Gilleland and Gillilan is derived from the Gaelic MacGill'Fhaoláin which means "son of the servant of (S.) Fillan." The Historical Research Center, a commercial "heraldic" business states that:"The Irish surname Gilliland is an Anglicization of the Gaelic Mac Giolla Fhaolain. The Mac Giolla Fhaolain was a sept [A division of a family, especially a division of a clan ] of the Ui Fiachrach and held their lands in the region of County Sligo. In modern times, however, Gilliland is most numerous in the northern counties of Derry and Antrim. This suggests that many modern bearers of this surname may trace their origins to the Scottish settlers who came to Ulster in the sixteenth and seventeenth centuries. There was a Scottish clan called Mac Gill'Fhaolain (son of the servant of Fillan) and this Scots Gaelic surname was also anglicized 'Gilliland'."