The battle of Ballynahinch was a military engagement of the Irish Rebellion of 1798 between a force of roughly 4,000 United Irishmen rebels led by Henry Munro and approximately 2,000 government troops under the command of George Nugent.

Approximately 4,000 rebels from Newtownards, Saintfield and Ballynahinch, equipped with artillery looted from Bangor harbour, gathered in one spot on 10 June and listened to a sermon given by Thomas Ledlie Birch.

Munro ordered his forces to occupy Ballynahinch on 11 June before establishing a camp at Montalto, the County Down estate of the Earl of Moira.

[1][2] On the morning of 12 June, Nugent, with a column of roughly 2,000 government soldiers (drawn from the Monaghan Militia, Fifeshire Fencibles and the 22nd Dragoons) and six 6-pounder guns and two howitzers manned by the Royal Artillery, marched onto Saintfield, where it was discovered to have no rebel presence.

Nugent's column, which was reinforced by detachments of the Argyll Fencibles and Downpatrick Yeomanry, moved onto Ballynahinch, where his men captured a rebel outpost before occupying the town.

[1][2] Some of his subordinates pressed Munro to attack Ballynahinch at night, noting that the "tired and hungry" Monaghan Militia (which formed a major part of Nugent's column) had looted the town and many of them were drunk.

Sixty-three houses in Ballynahinch were burnt by Nugent's forces during the battle, most of them on the night of 12 June as his men became drunk and started to loot the town, causing 20,000 pounds of damage.