Dillon, Theobald (d. 1691), 7th Viscount Dillon , Jacobite officer, was born at Lough Glynn, Co. Roscommon, eldest son of Capt. Robert Dillon and his wife Rose, one of the Dillon family of Streamstown, Co. Galway. In 1682 he succeeded as 7th Viscount Dillon on the death without issue of Lucas, 6th viscount. A staunch supporter of James II (qv), he was made lord lieutenant of Co. Roscommon and served as a lieutenant-colonel in the earl of Clanricard's regiment. In 1688 he raised two regiments for James II's army, placing two of his sons, Henry (later 8th viscount) and Arthur Dillon (qv), in command; the regiment commanded by Arthur was later transferred into the French service. He sat in the house of lords in James's Irish parliament (7 May 1689) and was outlawed by a Williamite attainder (May 1691). Serving with Clanricard's regiment throughout the Jacobite wars, he was present at the battle of the Boyne (1 July 1690) and prominent in the defence of the village of Oldbridge, a crucial position in the Jacobite line. He was killed at the battle of Aughrim (12 July 1691) and has no known grave.
He married Mary, daughter of Sir Henry Talbot of Mount Talbot, Co. Roscommon, and niece to the earl of Tyrconnell (qv); she was killed by an exploding shell during a bombardment at Limerick, 7 September 1691. They had three sons, the second of whom (Henry) succeeded as 8th Viscount Dillon when the act of attainder was removed in his favour (June 1694). There are some papers of Theobald Dillon in the Oxford county record office.