The second Battle of Arklow takes place on June 9, 1798 during the Irish Rebellion of 1798 when a force of United Irishmen from Wexford, estimated at 10,000 strong, launch an assault on the British-held town of Arklow, County Wicklow, in an attempt to spread the rebellion into Wicklow and to threaten the capital of Dublin.

A British advance force of 400 is defeated at Tuberneering on June 4. This rebel victory punches a hole in the dragnet the military has attempted to throw around County Wexford and also yields them three artillery pieces. The town of Arklow has been evacuated in the ensuing panic but the rebels content themselves with taking the town of Gorey and staying within the Wexford border. On June 5 the rebels attempt to break out of County Wexford across the River Barrow and to spread the rebellion but are halted by a major British victory at the Battle of New Ross. When the rebels finally move against Arklow, the town has been reoccupied by a force of 1,700 men sent from Dublin under Francis Needham, 1st Earl of Kilmorey, who quickly fortifies the town with barricades and has artillery positioned on all the approaches to the town.

The rebel army that forms for attack on the afternoon of June 9 is a combined force of Wexford and Wicklow rebels led by Billy Byrne, Anthony Perry, Conor McEvoy, Edward Fitzgerald, and Fr. Michael Murphy. The British in Arklow consist of approximately 1,000 militia from counties Antrim and Cavan and 150 regular cavalry supported by 250 Yeomanry. They are joined by 315 Durham Fencibles (Princess of Wales’s Fencible Dragoons) arriving an hour before the rebels.

The area surrounding the town and the approaches is covered by scrub and the rebel strategy adopted is to advance under cover attacking the town simultaneously from several points. Before the action begins, the rebels under Esmonde Kyan open fire upon the town with some of the artillery captured at Tuberneering and have some success by scoring a direct hit on a British artillery position, destroying the cannon and killing the attendant crew. The main assault is quickly launched but at all entry points the Irish are thrown back by the musket fire of the well-trained and disciplined militia and volunteers, and canister shot from the 3 pounder battalion gun brought by the fencibles. An attempt by the British to turn the Irish failure into a rout is defeated when pikemen and sharpshooters drive a cavalry charge back across the River Avoca, but an attempt to force a way into the town through the outlying fishing port is bloodily repulsed.

As Irish casualties mount, the lack of ammunition and proper leadership begin to work against them, and after Fr. Murphy is killed leading a charge, their attacks start to fade. As nightfall comes, the rebels begin to withdraw under cover of darkness and collect their wounded. They are not pursued or molested by the garrison who are, unknown to the rebels, down to their last three or four rounds per man and are themselves at the brink of defeat.

While rebel casualties are estimated at about 1,000 no full casualty list seems to exist on the British side, but are probably in the region of 100 dead and wounded. The defeat at Arklow marks the third failure to extend the fight for Irish independence beyond the borders of County Wexford following the other bloody repulses at New Ross and Bunclody. The Irish strategy now changes to a policy of static defence against the encroaching British armies.