Oranmore Castle was likely built by the Earl of Clanricarde between the 13th and 15th centuries and possibly on the site of a previous castle. It was used as a stronghold and in March 1642 the town, Oranmore, joined Confederate Ireland in a rebellion against which the then owners, the Marquess and fifth Earl of Clanricarde, the castle held out. Clanricarde was supplied by Fort of Galway from the sea until 1643 when, without the Marquess’s approval, the Governor of Galway surrendered. Possession was temporarily lost and regained and in 1666 it was leased to Walter Athy whose descendants retained control until 1853.
Left abandoned in 1853, it fell into disrepair and was then reroofed by Lady Leslie for her daughter, Anita Leslie in 1947 who then purchased it for £200. Later a two story wing was added. However, in 1964 the castle was set alight to provide heat for the winter and the new roof – the aesthetics of which some disapproved – was reduced to ashes. The daughter of Anita Leslie continues to reside there with her husband, noted musician Alec Finn of De Danann.
Oranmore has been featured in the March 23, 2001 episode of The Scariest Places on Earth as it is said to be haunted.