But the severest defeat which the confederates had was in the heart of Leinster, at the hamlet of Kilrush, within four miles of Athy.

Lord Ormond, returning from a second reinforcement of Naas and other Kildare forts, at the head, by English account, of 4,000 men, found on April 13 the Catholics of the midland counties, under Lords Mountgarrett, Ikerrin, and Dunboyne, Sir Morgan Cavenagh, Rory O'Moore, and Hugh O'Byrne, drawn up, by his report 8,000 strong, to dispute his passage.

With Ormond were the Lord Dillon, Lord Brabazon, Sir Richard Grenville, Sir Charles Coote, and Sir T.Lucas.The combat was short but murderous.
The confederates left 700 men, including Sir Morgan Cavenagh and some other officers, dead on the field; the remainder retreated in disorder, and Ormond, with an inconsiderable diminution of numbers, returned in triumph to Dublin.

For this victory the Long Parliament, in a moment of enthusiasm, voted the lieutenant-general a jewel worth 500 l.

If any satisfaction could be derived from such an incident, the violent death of their most ruthless enemy, Sir Charles Coote, might have afforded the Catholics some consolation.