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.