The Sack of Killarney occurred on 20 September 1642 when the Irish Confederate guerrilla leader Seamus Hennessey sacked the Irish village of Killarney amid the Irish Confederate Wars.
After a series of skirmishes with Parliamentarian patrols in Desmond, Hennessey led his band of irregulars to deprive the Parliamentarians of their control over County Kerry and County Cork. On 20 September 1642, Hennessey and his band visited the village of Killarney, where they spent several hours sacking the defenseless town. They reaped a rich horde of honey, barley, and other goods, in addition to currency, all without opposition. After putting Killarney to the torch, the Confederates returned to Limerick to sell off their plunder, making Hennessey over 1,000 pounds and enabling him to attract more recruits to his increasingly profitable cause.