This interesting surname, established in Scotland and Northern Ireland from an early date, is an Anglicized form of the Gaelic "Mac Giolla Ruaidh", composed of the element "Mac", son of, "giolla", servant of, youth, and "ruaidh", red (haired); hence, "son of the red (haired) youth". The sept originated in County Fermanagh where the placename Ballymackilroy is found: their territory was on the east side of Lough Erne. There is another Ballymackilroy in County Tyrone and a Ballymacilroy in County Antrim. Traditionally, Irish family names are taken from the heads of tribes, revered elders, or from some illustrious warrior, and are usually prefixed by "O", grandson, male descendant, or "M(a)c", denoting "son of". The surname has many variant spellings ranging from McIlroy, McGilroy, McElree, McElrea, and McAlroy, to Gilroy and Kilroy. The McElroys were of some importance in Gaelic Ireland, particularly in the 15th Century, as their frequent mention in the Annals of the Four Masters and Loch Ce testifies. Rev. John McElroy, S.J. (1782 - 1877), was a native of County Fermanagh, where he was educated at a hedge school and was associated with the United Irishmen in 1798. He was famous in America as a missionary priest and church builder. Mary McElree was recorded in Maghera, County Derry, on June 5th 1845, and James McElrea at Cappagh by Omagh, County Tyrone on April 3rd 1855. On March 13th 1846, Mrs. Ellen McElroy (51 yrs.), along with her children, John (19 yrs.), William (15 yrs.), Sally (14 yrs.), and Charles (12 yrs.), famine emigrants, departed from Liverpool aboard the "Ohio", bound for New York. The first recorded spelling of the family name is shown to be that of Michael M'Gilrey, which was dated 1376, in the "Ancient Charters of the Earldom of Morton", during the reign of King Robert 11 of Scotland, 1371 - 1390.