It is the oldest still established unit of the Army, and is headquartered in Stephens Barracks, Kilkenny as part of 1st Brigade.

In 1941 the battalion became the spearhead of the newly formed 5th Infantry Brigade, responsible for defending the southeast of the country from possible invasion.

Personnel from the battalion have seen service all over the world as part of Irish peacekeeping contingents, both within and outside the structure of the United Nations.

Today, the battalion forms part of 1st Brigade, contributing soldiers not only for the defence and security of the Republic of Ireland, but also for deployment overseas.

The battalion has served in various UN missions in trouble spots abroad including Congo, Lebanon, Liberia and Cyprus.