The Battle of Vinegar Hill, an engagement during the Irish Rebellion of 1798, takes place on June 21, 1798 when over 13,000 British soldiers launch an attack on Vinegar Hill outside Enniscorthy, County Wexford, the largest camp and headquarters of the Wexford United Irishmen. It marks a turning point in the rebellion, as it is the last attempt by the United Irishmen to hold and defend ground against the British military. The battle is actually fought in two locations: on Vinegar Hill itself and in the streets of nearby Enniscorthy.

By June 18, the British have surrounded County Wexford with between 13,000 and 18,000 troops and are ready to pour into Wexford to crush the insurgency. The United Irishmen leadership issues a call to all its fighters to gather at Vinegar Hill to meet the army in one great, decisive battle. The number assembled is estimated at between 16,000 and 20,000, but the majority lack firearms and have to rely on pikes as their main weapon. The camp also includes many thousands of women and children who are staying there for protection against the rampaging military.

The British plan, as formulated by General Gerard Lake, envisages the complete annihilation of the United Irishmen, women and children by encircling the hill and seizing the only escape route to the west, the bridge over the River Slaney. Lake divides his force into four columns to accomplish this. Three columns, under Generals David Dundas, James Duff and Francis Needham are to assault Vinegar Hill, while the fourth column, under General Johnson, is to storm Enniscorthy and its bridge.

The battle begins shortly before dawn with an artillery bombardment of Irish positions on the hill. Advance units quickly move against the United Irishmen outposts under cover of the bombardment and move artillery closer as forward positions are secured. The tightening ring forces the United Irishmen into an ever-shrinking area and increases exposure to the constant bombardment, including new experimental delayed-fuse shells resulting in hundreds of dead and injured. At least two mass charges are launched by the United Irishmen which fail to break the lines of the military and the situation on Vinegar Hill soon becomes desperate for the United Irishmen.

Meanwhile, a detachment of light infantry under the command of General Johnson attacks the town of Enniscorthy but meets with fierce resistance. Buildings in the town have been fortified and the initial attack is driven back with the loss of munitions and men. A second attack commences with reinforcements including cavalry, which retake the lost cannon and ammunition while also incurring considerable casualties. The United Irishmen are slowly driven out of the town but manage to hold the Slaney bridge and prevent the British from crossing.

When British troops crest the eastern summit of Vinegar Hill, the rebels begin to slowly withdraw through a gap in the British lines later known as “Needham’s Gap”, so-named because the late arrival of General Needham’s troops prevented a total encirclement of the hill. Although the bulk of the United Irishmen army escape, many are left behind and killed in the routing phase of the battle from both cavalry and infantry attack, but also from the advanced field guns which are switched to grapeshot to maximize casualties.

In addition to conventional casualties, there are also instances of British troops raping the women accompanying the United Irishmen and in Enniscorthy, United Irishmen wounded are burned to death when soldiers set fire to a building used as a casualty station. These atrocities may have been perpetrated in revenge for the execution by the United Irishmen of numbers of mostly Protestant loyalist prisoners of war in the preceding weeks. The United Irishmen abandon much of the supplies they had taken from surrounding areas, and thirteen cannons are captured by the British, a number of which had been taken from the British forces previously.

Meanwhile, the bulk of the United Irishmen force streams uninterrupted towards the Three Rocks camp outside Wexford and, following the decision to abandon the town, split into two separate columns in a new campaign to spread the rebellion beyond Wexford. One immediately sets out to the west, the other northwards towards the Wicklow Mountains to link up with General Joseph Holt‘s forces.

The defeat is therefore not the immediate crushing blow to the Wexford United Irishmen that it has falsely been depicted as, but it does alter the course of the fighting as continued resistance now takes the form of mobile warfare, raids, and large scale, guerilla-type operations.

Casualties for the United Irishmen have been variously reported, with estimates ranging from 400 to around 1,200. Kevin Whelan estimates a figure of between 500 and 1,000 including camp followers, while Archibald McLaren, a British soldier eyewitness, writes that the United Irishmen casualties total about 1,200 men. British casualties are around one hundred.