The Irish Unification of 2024 was an event in Earth history taking place in Ireland. It resulted in the creation of a single unified nation-state controlling the entire geographical island of Ireland, which up until that time had been divided between the nation-state of the Republic of Ireland (presumably) in the south, and territory in the north which was part of the United Kingdom. This unification came about due to the use of terrorism rather than peaceful acts to bring about political change.
In 2366, the Irish Unification was noted by Lieutenant Commander Data as one of the numerous examples in history where terrorism was successfully used to bring about political change. Other examples he listed were the independence of Mexico from Spain, and the Kenzie Rebellion. (TNG: "The High Ground")