The McCowans of Argyle are not connected with the McCowans of Ayrshire. The Argyle McCowans on the west coast of Scotland are evidently the group with the MacGillchomghain origins -- son of the servant of St. Comgan. It is possible that some of the Argyle McCowans or McEwans followed the Campbells into Perthshire, where many used the spelling McOwan.
Leading Winnipeg architect, Hugh McCowan, was of the Argyle group.
The McCowans' Who's Who, Vol. 11