[3] They were ousted by the Uí Dúnlainge from the lowlands of what later became County Kildare, and from that time until the early 13th century were located along the western foothills of the Wicklow mountains.
[citation needed] Derrynamuck in the Glen of Imaal is a cottage dedicated to the memory of Michael Dwyer, a celebrated leader of the Irish Rebellion of 1798.
[6][7] On 16 September 1941, the glen was the site of the worst single incident involving loss of life in the history of the Irish Defence Forces.
[8][9][10] This incident, known as the Glen of Imaal Disaster,[11] occurred during a training exercise involving 27 officers and men from the army's anti-aircraft battalion, artillery school, and corps of engineers.
[12] Sixteen soldiers were killed when an antitank mine unexpectedly exploded (15 dying immediately, and one later succumbing to his wounds).
[15][16] On 15 April 1979, a fatal accident occurred in the glen when a group of teenagers from Lucan who were engaging in an orienteering activity triggered an explosive which subsequently detonated, killing three and seriously injuring others.
[20] Tactical exercises also take place there, sometimes involving Mowag armoured personnel carriers and Irish Air Corps helicopters.