Quote Originally Posted by JSFMACLJR View Post
"Mc" and "Mac"...it doesn't matter. Really. My MacLean forebearers left the Isle of Mull, spelling their surname McLean. Two generations later it was MacLean.

The spelling issue is a total fabrication, as far as denoting Scottish heritage. The use is interchangeable, due to notoriously poor spelling abilities! As to how the Irish do it, I just don't know.
Norman Maclean has an interesting comment about the spelling of his surname in A River Runs Though It; when his father, the Rev. Maclean, finds out that his younger son Paul has changed the spelling of their name to "MacLean", he remarks sadly that now "everyone will think we're Lowlanders and not Islanders."

It's not only in the story, but in the movie as well.

T.