I put together a 9 page disertation on the McGuffin name and could send it as an attachment to someone that is interested. Theperson that suggested McFee or MacPhee is on the right track. They were originally on the Island of Colonsay but were displaced during Clan wars and settled on the "Mainland" i.e. Glasgow, Mull of Kintyre and surounding areas. McFee evolved to Macafee -> Macuffee -> MacGuffie (McGuffie) -> McGuffin(McGaffin). They came over to Ireland starting in the 1600's and some to N. America in the 1700's when the British started colonizing. Most came over from Ireland circa 1800 as famines and other troubles beset the country and it's peoples.