The Battle of Ballymore-Eustace is one of the events in the United Irish rebellion of 1798. It takes place on May 24, 1798, after the stationing of the 9th Dragoons, and members of the Tyrone, Antrim and Armagh Militias at Ballymore-Eustace in County Kildare near the border with County Wicklow on May 10. The town has been recently garrisoned by almost 200 soldiers and militia who have been sent to repress sedition in the area. The troops have been dispersed in billets among the populace as per counter-insurgency practice of “free-quarters” where responsibility for the provisioning and sheltering of militia is foisted onto the populace. During this time a quantity of arms are surrendered and letters of protection issued.

On May 23, one hundred twenty soldiers are recalled, leaving a garrison of around 80 men. At around 1:00 a.m. on May 24, the rebel force of approximately 200 attack the town. As in the attacks on Naas and Prosperous, the rebels seek to surprise and overwhelm the garrison by coordinated attacks before it can react and rally against them. The houses containing troops of the 9th Dragoons and the Tyrone Militia are to be attacked simultaneously.

However, the attack on garrison headquarters is miscarried due to lack of coordination and numbers so that the building becomes a rallying point for the Government troops. Captain Beevor is attacked in his own bedchamber by two rebels. Lieutenant Parkinson and some dragoons come to his aid and both rebels are slain. Other isolated billets are attacked but some units manage to cut themselves free and fight their way through the streets to the headquarters. A number of properties, including the Protestant church, are set on fire.

For two hours, the rebels attack the strongpoint but, without artillery, are unable to take the building and lose many men in the process. The momentum has by now slipped away from the rebels and they draw off their attack leaving behind around 50 dead but at a cost to the garrison of at least 12 dead and 5 wounded.

The battle leads directly to the Dunlavin Green executions, in which fears of a possible rebel attack on the garrison at nearby Dunlavin lead to the summary execution of rebel prisoners.