 McNeill was the brother-in law (by his 2nd marriage) of the author John Wilson, and (by his 3rd marriage) of George Campbell, 8th Duke of Argyll.McNeill died at Poralto near Cannes in France, on 17 May 1883.A memorial to his memory lies on the south-east wall of Liberton Cemetery in Edinburgh, at the grave of his third wife, Emma Augusta.