This is just one of the many historic sites in the county with other castles at Rhuddlan, Ruthin and Dinas Bran near Llangollen.
St Asaph's ancient cathedral is the smallest in Britain. William Morgan, who was Bishop of St Asaph in the early 17th century, was responsible for translating the Bible into Welsh.
Towns like Ruthin and Denbigh contain great examples of historic architecture and their peaceful settings contrast sharply with the often violent episodes of their past.
Ruthin was almost completely destroyed in 1400 when Owain Glyndwr attacked the town while Denbigh Castle was attacked and besieged during the Civil War in 1646.
Other sites in the county date back even further.
Offa's Dyke, thought to have been constructed in the 8th century, begins at Prestatyn which is also where Roman remains have been unearthed.
Rhyl has a long history as a seaside resort and has been attracting visitors since Victorian times.
Another town which draws visitors to the area is Llangollen with its many historic sights, including Plas Newydd, the home of the well-known Ladies of Llangollen in the 18th century.
Just outside Llangollen is Valle Crucis Abbey, former home to Cistercian monks, and nearby Eliseg's Pillar with its ancient inscription, thought to have been in existence since the 9th century.
The county of Denbighshire is steeped in history, though it has only been in existence in its present form since 1996, when local government reorganisation created three counties from the former Clwyd.