McGill's major assets included real estate in Lower and Upper Canada and investments in Britain; the latter not specified as to character or amount. There were also extensive mortgage holdings. In his will, old friends were remembered, the Montreal poor, the Hôtel-Dieu de Montréal, the Grey Nuns, the Hôpital-Général de Québec and two Glasgow charities. Even though Alexander Henry grumbled that McGill's fortune, "went to strangers... (and) his wife's children, Mrs McGill is left comfortable, but young Desrivières (the son of McGill's youngest stepson) will have £60,000".