The current Gothic Revival structure, built between 1826 and 1835, replaced an earlier Georgian mansion that had itself succeeded the original tower house. The O’Brien family, descendants of Brian Boru and one of Ireland’s most powerful Gaelic dynasties, held the estate for over 900 years before selling it in 1962.

The original fortification was likely built in the early 1500s by one of the O’Brien chieftains, though the exact date remains uncertain. Historical records from Risteárd Ua Cróinín and Martin Breen’s survey of Clare’s castles suggest the site may have been fortified even earlier, given its strategic position overlooking the River Rine. The tower house would have been a typical Irish defensive structure of its time; a rectangular stone building rising several storeys, with thick walls, narrow windows, and battlements designed to withstand siege warfare during the turbulent medieval period.

Today’s castle bears little resemblance to its martial origins, having been transformed into one of Ireland’s premier luxury hotels. The surrounding 450-acre estate includes formal gardens, a golf course, and the original walled garden that dates to the 18th century. Despite its grand Victorian Gothic appearance, careful observers can still spot remnants of the earlier structures incorporated into the current building’s foundations and lower walls, physical reminders of Dromoland’s centuries as a seat of Gaelic power in Thomond.