The original castle dates back to the 13th century Anglo-Norman castle built by the de Burgos family after their defeat of the native O'Connors of Connaught. Successive lords expanded the castle and fortified it. The central building, a French style chateau that incorporates the 13th century castle, was built in the mid 1700's by Lord Ardilaun. In 1852, the castle became the country home of the Guinness family.

Ashford Castle is located in the town of Cong. The film The Quiet Man, starring John Wayne and Maureen O'Hara, was filmed in Cong and the surrounding area included Ashford Castle.