 Through this marriage, he became associated with the seigneuries of Mingan and Jolliet and property on Île Sainte-Hélène.Mrs Grant's daughter by her first marriage inherited her father's title, becoming the 4th Baroness de Longueuil.Grant arranged a marriage between the Baroness and his nephew, Captain David Alexander Grant (1753-1806) of the 94th Regiment of Foot (1780).