Several years ago I wrote the Clan Muir Society and asked them for their permission for to wear their tartan, since I am a seasonal US National Park Ranger, and one supporter of our National Park System was Scotsman John Muir. The Society's secretary enthusiastically responded "yes" to my request -- although I have not been able to do so yet, I would imagine that "yes" still stands.

Bottom line: There is no "right" to wear a particular tartan, save "restricted" tartans such as the Balmoral Tartan and some clan/family tartans wear you must by the material from the Chief and/or society and prove descent. Thompson says:

The dictionary definition of rights lists three kinds: legal, moral and divine (as in "the divine right of kings.") Since it has never been suggested that any use of the tartan is illegal, immoral and ungodly, it is meaningless to talk about anybody's right to any tartan.
A connection to a tartan, however large or small, is better than no connection at all, but even no connection to a tartan is not "wrong" either. Again, bottom line: if you have the connection, and like the tartan, then wear it. I would recommend joining the Clan Society (if there is one) of the tartan you are wearing -- most clan societies, save a few, allow anyone to join, regardless of "blood" -- and that is what many clans in days of old practiced anyway.

My father's family are also Irish. County Tyrone, hence my use of Jer "Mc" as a screen name.
I used to hear this a lot when I worked as a genealogy librarian, but "Mac v. Mc" defining whether one was Scottish or Irish is pure myth. "Mc" is an abbreviation of "Mac", plain and simple, and sometimes you even see M ' as the abbreviation -- nothing more than the product of a lazy clerk or immigration officer! :mrgreen: You find Macs and Mcs in both Scotland and Ireland.

Cheers,

T.