Fourth Northern Division of the Irish Republican Army

The Fourth Northern Division of the Irish Republican Army operated in an area covering parts of counties Louth, Armagh, Monaghan, and Down during the Irish War of Independence and Civil War. Frank Aiken was commander and Padraig Quinn was the quartermaster general. John McCoy was Adjutant General for the division; after he was shot and captured by British Crown forces in 1921 Sean F. Quinn, Padraig's brother, took over the position.

At the outbreak of the Civil War, the Fourth Northern Division was neutral and in control of the Dundalk military barracks after the British army vacated it on April 13, 1922. Aiken was in Dublin with Richard Mulcahy (Chief of Staff of the IRA until the split), arguing against the Free State taking military action against a large anti-treaty IRA force which had taken over the Four Courts. Mulcahy ordered Aiken back to Dundalk.

On July 4 Aiken wrote to Mulcahy stating the Fourth Northern Division would stay neutral, called for an end to the fighting and for the removal of the Oath of Allegiance from the Treaty because “you have the simple national abhorrence of swearing allegiance to a foreign king and allowing part of the Nation to be ruled by people who have a sworn loyalty to that king.”

On July 15 Aiken again met in Dublin with Mulcahy, arguing for peace. The following day Mulcahy's men came as friends to Dundalk and captured Aiken's barracks through a breach of faith, and Aiken and his officers and men were imprisoned in Dundalk jail. On July 27, Padraig Quinn (who during the Anglo-Irish War also commanded a unit that operated against the British in Dublin city centre) led a small unit that attacked Dundalk, breached the prison wall with dynamite, and in fifteen minutes captured the garrison of 300 men and arms for 400. There no casualties during the jail break. A number of escaping divisional members were recaptured by Free State forces, including John McCoy of Mullaghbawn, who was a brigadier in the barracks before the Free State troops took command.

On April 23, 1923, Aiken was elected chief-of-Staff of the IRA and an Army Council composed of him, Pilkington and Tom Barry was appointed. Sean F. Quinn succeeded him as officer commanding the Fourth Northern Division. On April 27, Aiken issued a ‘Suspension of Offensives’, a command that all offensive operations should be suspended from noon on 30 April. This marked the end of the civil war.