"Mac" vs. "Mc": No Religious Divide

Absolutely not. Both "Mac" and "Mc" are Scottish and Irish Gaelic patronymic prefixes meaning "son of." They are orthographic variants—Mc is simply an abbreviation of Mac (the 'a' omitted, often with superscript 'c' historically: M^c).

Key Facts

• Origin: Old Irish mac ("son").
• Geography: Both used in Scotland and Ireland. Mc more common in Ulster (NI) and America; Mac more common in Highlands/Scotland. But both appear everywhere.
• Religion: Zero correlation. Catholic and Protestant families share both prefixes. Examples:
  • Catholic: MacDonald, McCarthy, McGuinness, MacLeod
  • Protestant: MacArthur, McCartney, MacKenzie, McDowell
• Sorting: In alphabetical lists, Mac and Mc are typically filed together under "Mac" (treating Mc as Mac).
• Other forms: M' (M'Donald), Mic (rare), O' (Irish "grandson of" – distinct).

The myth of a Catholic/Protestant split is a 19th-century sectarian fabrication (often anti-Irish/Catholic propaganda). Genealogically and linguistically, they are identical.