The spelling Atholl is more frequent as a placename in Scotland. This is the spelling of the main district in the highlands and the historical Earldom. I think Athol is more common as a surname, and hence I would say that the first name in this spelling is more likely to have come from the surname rather than the place name.
I think Athol is more common as a surname, and hence I would say that the first name in this spelling is more likely to have come from the surname rather than the place name.