Originally thought to be an Englished form of Mac'illeghuirm: "son of the blue-eyed lad". The lad is assumed to have been a M'millan; though nothing is known about who he was, where he lived or when. It has been suggested more recently however that the original Gaelic name which has been Englished to "Blue" in fact had nothing to do with that colour at all, and was actually Mac Ghille-Ghuirman ("Son of the Devotee of St. Gorman"), which in the light of the MacMillans' connections with other saintly cults does not look unlikely. The Blues in North America have their own organisation - loosely connected to Clan MacMillan - which also welcomes members from other parts of the world:
The Sept of Blue, P.O.Box 5444, Lenoir, NC 28645, USA.