Fonmon Castle is a fortified medieval house near the village of Fonmon in the Vale of Glamorgan. It dates from the 13th century, and is still in use as a private residence. The walled gardens are surrounded by woodlands.
The present owners, the Boothby Baronets, are descendants of Colonel Philip Jones, who bought the house in 1656. Notable features include the library, designed by Thomas Stocking.
The castle is open to the public during the summer months, and the grounds are often used for public events.