McGirr is an Irish Gaelic Surname. It may be derived from an epithet or may be a calque or Phono-semantic match to the Irish word gearr which translates as Short. According to the Irish Times Households in the 19th Century database, 'Gear' as a surname was found to be exclusive to Cork, Kerry, Limerick, Kilkenny and Offaly with the majority in Kerry. However 70% of McGirr households in the 19th Century were found in Tyrone and almost exclusively in Ulster. The name McGirr is certainly most common in Tyrone and is associated with the Cenél Fearadhaigh of Clogher.
The Annals of Ulster tell us that Cu-Uladh (The hound of Ulster) McGhirr-McCawell (MacCathmhaoil), 'chieftain of his own tribe', was an illustrious Professor of science in England in 1368. In the aftermath of the potato famine with the mass emigration of Irish it was very common for Irish to conceal their roots to avoid discrimination and names were commonly changed, i.e. O'Donnell to Dodds. There are Shorts listed in Kirkcudbrightshire east Scotland and a few McGirrs; however, the McGirr name is far more prominent in Ireland than in Scotland. The Ulster Annals show Cu-Uladh McGhirr-McCawell(MacCathmhaoil) was perhaps too well established to be among the gallóglaigh. Edward Shortt, the son of a vicar who served as British Home secretary in the 1920s, has Family roots which originate from Co. Tyrone.
Feradach, of the Cenél Fearadhaigh, was the son of Muiredach, and great-grandson of Niall whose descendants included the MacCawells (MacCathmhaoil), as well as the Irish Campbells in the Clogher area. MacGilmartin were chiefs in the barony of Clogher, and one was chief of Cenel Fearadaigh in 1166.
In 1365 when Malachy of the Mac Cathmhaoil, the ruling house of Clogher, slew an O'Neill of Tír Eoghain, Malachy was known as ‘Maelechainn mac in ghirr meic Mac Cathmhaoil’. Translated his name is Malachy the son of the Short-Fellow Mac Cathmhaoil. This feat of slaying an O’Neill warranted a change of name so he became Malachy mac in ghirr or simply Malachy MacGirr. Later this family survived the Ulster Plantation, receiving a number of grants of lands at the time. They are to be found later in the 1660s as taxpayers in the Clogher Valley and elsewhere in Tyrone. Today the family is generally found as McGirr, McGerr, McKerr and in the anglicised version as Short.