The Battle of Ballinaculla was fought between Seamus Hennessey's Irish Confederate company and a troop of Anglo-Irish deserters in County Roscommon in 1642.
The Irish Rebellion of 1641 created a state of civil war in Ireland as forces loyal to the English Royalist administration in Dublin, Scottish Covenanters in Ulster, Parliamentarian colonists in County Cork, and Irish Catholic Confederates fought for control of the island. During the conflict, several bands of underpaid soldiers deserted their armies and became highwaymen. Several Catholic irregulars, called rapparees, waged a guerrilla war against Protestant forces across the island, and Seamus Hennessey departed from Kilkenny in September 1642 to assemble his own band of irregulars from County Roscommon and County Dublin to County Galway.
On 13 September 1642, his band of 15 irregulars faced their first battle when a troop of 10 Anglo-Irish cavalrymen, who claimed to be "free" and fought only for themselves, intercepted them at Ballinaculla as the Irishmen attempted to cross the River Shannon. Hennessey and his poorly-equipped recruits decided to face the enemy in battle, and, in the ensuing conflict, many of the Anglo-Irish horsemen fell into the River Shannon during their failed charge against the Irish peasants. The Irishmen then charged into the river and dispatched the cavalrymen, who were now deprived of their shock value. Only one Irishman was killed during the destruction of Lamber's force.