12 May - Siege of Galway - Thomas Preston, the military governor of Galway, surrenders the city to English Parliamentarians commanded by Charles Coote. Galway was the last city held by Irish Catholic forces.
May - The largest Irish guerrilla forces under John Fitzpatrick (in Leinster), Edmund O'Dwyer (in Munster) and Edmund Daly (in Connacht) surrender, under terms signed at Kilkenny, allowing Irish troops to go abroad to serve in foreign armies not at war with the Commonwealth of England.