Recorded in many forms as shown below, this is a Gaelic surname, associated with both Ireland and Scotland. It originates from the pre 10th century Mac giolla Ruaidh, meaning "The son of the servant of the red haired youth", and possibly a reference to a Dane or Norseman. The sept originated in County Fermanagh at Ballymackilroy, on the east side of Lough Erne. There are other Ballymackilroy's in County Tyrone and County Antrim. Traditionally, Irish family names are taken from the heads of tribes, revered elders, or from some illustrious warrior. This surname has spellings ranging from McIlroy, McGilroy, McElree, McElrea, McElwee, McAlroy, MacKilroy, Kilroy, Gilroy and others. The McElroys were of 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. 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.