| Background: Originally from Ireland, one family of whom became extensive landowners in Co. Limerick and are perpetuated there in the place name Mountfox, near Kilmallock. The Irish Foxes got their name as a sobriquet: Tadhg O Catharnaigh (anglice O'Caherny - mod. Carney or Kearney), Chief of Teffia, Co. Meath (d. 1084) was called Sionnach, I.e The Fox, and in due course this branch acquired the name Fox as a distinct surname.
Variations: Fox, McFox, McShanaghy, McShinagh, McShinnock
More Info: http://heraldry.celticradio.net/search.php?id=86
Discussion of this family is welcomed.