It incorporates a large drum tower with a circular saloon inside (which overlooks the sea), a grand oval staircase and a suite of well-appointed apartments.
The castle was the venue, on 14 November 1817, when the 1st Marquess of Ailsa's daughter, Margaret Radclyffe Livingstone Eyre, married Thomas, Viscount Kynnaird.
In doing so, they stipulated that the apartment at the top of the castle be given to General of the Army Dwight D. Eisenhower in recognition of his role as Supreme Commander of the Allied Forces in Europe during the Second World War.
On 24 June 1961, the regiment returned to the castle to be presented with its first guidon by General Sir Horatius Murray, KBE, CB, DSO.
The castle re-opened in April 2011 after a refurbishment funded by a gift in the will of American millionaire William Lindsay to the National Trust for Scotland.