The castle’s origins trace back to 1199, when King John granted five knight’s fees to William de Burgh with the condition that he erect a fortress here. Even before the Anglo-Norman arrival, this strategic location housed an Irish residence called Caslaun Uí Chonaing, where in 1174 the O’Brien princes Dermot and Mahon met a grim fate, blinded by their relative King Donald. The de Burghs, later known as the Bourkes, would transform this site into a formidable castle that measured approximately 49 metres by 30 metres, featuring circular towers at its corners that bore a striking resemblance to those of King John’s Castle in Limerick.

Throughout the medieval period, Castle Connell changed hands frequently, reflecting the volatile politics of Anglo-Norman and Gaelic Ireland. The fortress suffered destruction by Conor O’Brien in 1261, was wasted by the Bruce invasion in 1315, and saw numerous transfers of ownership between powerful families including the de Burghs, Butlers, and de Clares. By the 15th century, it had become the seat of the Bourke family, with William Bourke being created Baron Bourke of Castleconnell in 1580 for his services against James of Desmond. The castle’s design was impressive; despite being built atop a six-metre high vertical-sided rock, its steps were constructed so cleverly that a troop of horse could be drawn up in its great hall.

The castle met its spectacular end during the Williamite War in Ireland. After initially surrendering to Cromwell’s forces in 1651, it later became a Jacobite stronghold until August 1691, when the Prince of Hesse besieged it for two days on behalf of William of Orange. Following the garrison’s surrender, General Ginckell ordered the castle to be blown up, considering it too strategic to leave intact. The explosion was so tremendous that it shook houses in Limerick several miles away and shattered windows throughout the city. Today, only fragments remain on the steep rock face; overgrown traces of walls, well-built arches, and remnants of two towers that once guarded this commanding position above the Shannon, where medieval power politics played out for centuries.