[1] Originally called Killorglin Castle, a defensive structure was first built on the site next to the River Laune by Maurice FitzGerald, 2nd Lord of Offaly.
[2] Following the Desmond Rebellions, the castle was seized by the Crown and subsequently granted to Captain Jenkin Conway in 1587 as part of the Munster Plantation.
[citation needed] Between 1700 and 1710, a new stately home was built by the Blennerhassett family on the site of the ruined castle, including elements of the medieval structure.
[4] By this stage, the family estate surrounding the castle was approximately 7,000 acres, and the Blennerhassetts were able to build a large new house, recorded as having tall chimneys, an important library and demesne terraced gardens leading down to the River Laune.
Castle Conway was inherited by Harman Blennerhassett in 1792, but was sold to his relation, Thomas Mullins, 1st Baron Ventry in 1795.