Madill Family Genealogy Forum
I am English, (now) living in London. I was born in Preston, NW England, but my father originally came from Belfast, my grandfather from (I think ) County Claire (at least it was a county just south of the current Ulster-Eire border).
The version I always heard was that the name came from France (possibly the old French word "masle"), and was transplanted to Ireland and North America (One story regards 3 brothers, one stayed in France, 2 emigrated to America, although one only got as far west as Ireland. I think this is a bit too simple to be true!). There's no real evidence of this. However, I believe the first record of the name in England may have been around the 11th century - indicating entry to England with the Norman invasion. The English line either died out or moved away, because current UK Madills all appear to stem from Ireland.
I don't know if this is correct, or just a story, but it might provide a point of research if anyone is desparate ti find out. Try the English Domesday book for possible Franco-Norman versions of the name, but note that you must use ancient French, not modern French, and may also help to think like an anglo-norman.