Culzean Castle, constructed as an L-plan castle between 1777 and 1792 by the 10th Earl of Cassilis, was designed by architect Robert Adam. It replaced a previous structure and served as the fine country house for the earldom. The castle features a large drum tower with a circular saloon overlooking the sea, a grand oval staircase, and well-appointed apartments.

In 1817, the castle hosted the wedding of Margaret Radclyffe Livingstone Eyre, daughter of the 1st Marquess of Ailsa, to Thomas, Viscount Kynnaird. The castle and its grounds were gifted to the National Trust for Scotland by the Kennedy family in 1945, with the stipulation that General Dwight D. Eisenhower, the Supreme Commander of the Allied Forces in Europe during World War II, be given an apartment at the top of the castle. Eisenhower visited the castle several times, including during his presidency.

Culzean Castle has historical connections, as the Ayrshire Yeomanry was formed there in 1794. In 1961, the regiment returned for a ceremony to receive its first guidon. The castle underwent refurbishment in 2011, funded by a bequest from American millionaire William Lindsay, who was intrigued by Eisenhower's visits. In 2019, Culzean Castle welcomed 333,965 visitors.