Gregans Castle lies in the Ballyvaughan valley of the Burren, a unique region that contains grey limestone terraces, a very high concentration of alpine, mediterranean and arctic flowers, particularly orchids, ancient burial tombs, stone forts and ecclesiastical ruins.
The 15th/16th-century tower house was the seat of the chief of the O'Lochlainn (or O'Loughlen) family, called the "Prince of Burren".
An early member of the Martyn family is recorded as having been killed at the Battle of Aughrim in 1691 at the end of the Jacobite wars.
[1]: 14 After his death, his son Francis Florence Martyn remained at Gregans and farmed a much reduced estate.
During these times of economic depression, the house fell into some disrepair and the unmarried Frank, locally thought of as an eccentric, died in 1956.
The oldest surviving feature of the house is the former kitchen fireplace with crest keystone in what is now the Martyn Suite.