Gallagher (surname)
Gallagher is the anglicisation of the Irish surname Ó Gallchobhair (or a newer spelling form: Ó Gallchóir), these being masculine forms; the corresponding feminine forms are Ní Ghallchobhair (newer form Ní Ghallchóir). Apart from the aforementioned spelling there are at least 30 recorded variants including Gallacher, Gallager, Gallaher, Galliher, Gallaugher, Galagher, Galegher, and Goligher.
It is the most common surname in County Donegal and the fourteenth most common by birth records in Ireland. In the United States, it was ranked by the 2000 U.S. Census as the 574th most common name out of over 80,000 surnames found. According to Professor Edward MacLysaght, in the mid 20th century Gallagher was one of the most common Irish surnames, most of the recorded births being located in the north-west provinces of Ulster and Connacht, with the majority being recorded in the homeland of the sept - Co Donegal.
Read more about Gallagher (surname): Ó Gallchobhair Sept, Gallagher Ecclesiastics in The 16th Century, 17th Century and The Flight of Earls, Arms, Origins