Magill, McGill A Scottish surname Mac an ghoill meaning “son of the Lowlander or stranger”. Macgill is a surname of Galloway. There were also Macgills in Jura, where they were known as Clann a’ ghoill. It may also be an abbreviation of the many surnames begining Mac Giolla, either Irish or Scots. In 1890 Magill was principally found in Antrim, Armagh and Down, McGill was found in Donegal and Tyrone, and the estimated number of bearers was 3,765 (including variants).