The O’Lochlainn clan, once styled Princes of the Burren, held this stretch of County Clare from a 15th-century tower house that still stands across the road from today’s hotel. Cromwellian commissioners granted the surrounding estate to the Martyn family in 1656, and their descendants built the Georgian mansion now known as Gregans Castle in 1750, seeking a more comfortable residence with sweeping views over Galway Bay. Captain John Gregory Martyn expanded the house considerably after taking up permanent residence in 1866, hosting the social gatherings that gave the property its lasting reputation.
Economic hardship later forced the family to let the house slide through various uses: a summer home in the late 1800s, a small working farm in the early 1900s, and finally an inn by the 1940s. It became Gregans Castle Hotel in 1967 and has been run by the Haden family since 1976. J.R.R. Tolkien stayed as a guest and is said to have drawn on the Burren’s stark limestone landscape while writing The Lord of the Rings, and Seamus Heaney was among later literary visitors.