While Clan Colquhoun had occupied the site of the present club since ancient times, the medieval
Rossdhu Castle was constructed by Sir John Colquhoun in 1457 along with the private chapel of St. Mary of Rossdhu when his lands were consolidated into the free Barony of Luss.
Rossdhu is derived from the
Scottish Gaelic '''', meaning the "black headland". The castle was ruined in a fire after the construction of Rossdhu Mansion and ruins can be seen directly behind the course's 18th green. The central portion of the present house, known as
Rossdhu Mansion, was completed in 1773. The grand
Georgian manor house was constructed by Sir James Colquhoun and was likely designed by well-known architect John Baxter to replace the 15th-century castle, though no documentation survives. This was the family seat when
Sir James Colquhoun, 3rd Baronet led the clan and the writer
Janet Colquhoun was his wife. Until the late 1970s, the house was home to
Sir Ivar Colquhoun, 8th Baronet, and Lady Colquhoun. They loaned many original pieces of furniture and artwork to the restored manor house in 1994, thus assuring that Rossdhu Mansion would be historically preserved notwithstanding ownership by the club. == Ownership and Paradise Papers revelations ==