 At the time of his birth his father was stationed with the 1st battalion of the Royal Highland Emigrants on Carleton Island, New York, where Lake Ontario empties into the St. Lawrence River.Later, after the Treaty of Paris was signed ending the American Revolutionary War the family briefly resided at Fort Oswegatchie (Ogdensburg, N.Y.) before moving to Montreal when Angus was still a very young child.By 1787 his father had moved once again to Glengarry County in what later became Upper Canada.