General Alexander Montgomery (c.1721—1785) was an Irish MP for County Monaghan, Ireland.
John had succeeded his father to the Ballyleck Estate when his elder brother Thomas was disinherited for marrying an Englishwoman.
His mother was Mary Coxe, a Maid of Honour to Queen Caroline, wife of King George II of Great Britain.
Died unmarried in Madras, India), Reverend Robert Montgomery (1753-1825 Rector of Monaghan, Ireland) 2.
Miss Eleanora Moore, daughter of Acheson Moore of Garvey, Tyrone, Ireland by whom he had Colonel Nathaniel Montgomery of Garvey, Revella and Fassaroe Castle, Co. Wicklow (Member of Parliament for County Tyrone.