 A sunken Dutch garden was created by Frances, Countess of Onslow at the north front of the house in the late 19th century.In 1895, the house was investigated for paranormal activity by the Marquess of Bute and Ada Goodrich Freer on behalf of the Society for Psychical Research.During World War I, the Onslow family created and managed a hospital in Clandon House for the war injured.