The title of Baron Inchiquin is one of the older titles in the Peerage of Ireland, dating to 1543. From 1654 to 1855 the Barons Inchiquin also held the titles of Earl of Inchiquin and Baron O'Brien, and was Marquess of Thomond from 1800 to 1855. In 1855, however, those titles became extinct. In the Irish nobility, the Baron continues to hold the titles of The O'Brien, Prince of Thomond and Chief of the Name of O'Brien.
