Family History and Genealogy Resources by Surname
McHarg Surname Origin
Welsh, Cornish British, and Gaelic) The son of the brave or the handsome. Mac 'Arg.
Source: An Etymological Dictionary of Family and Christian Names With an Essay on their Derivation and Import; Arthur, William, M.A.; New York, NY: Sheldon, Blake, Bleeker & CO., 1857.
McHarg Surname Meaning and Family Facts
There is more to McHarg family history than the origin of your surname:
A McHarg Family History Thought:
'The past isn't dead. It isn't even past.' --William Faulkner