Quote Originally Posted by M. A. C. Newsome View Post
I think it would be more accurate to say that some named MacKay were part of the Clan Donald -- it would NOT be accurate to say that the Clan MacKay itself was a sept of the MacDonalds. Remember, what clan one belonged to really had very little to do with surname and a lot to do with geography.

I find that the Clan Donald web site has much more information than most when it comes to explaining sept relationships. They do, indeed, list MacKay as a Clan Donald surname, with these notes:
Agreed, the name MacKay = Son of Kay (in the most basic form). Just like; not all MacDonalds are part of clan Donald.