Carndochan Castle (Welsh: Castell Carndochan) is a stone castle near Bala in Gwynedd, north Wales built in the thirteenth century. Its early history is unrecorded, and it would seem to have been built by one of the three major princes of Wales to have governed in the thirteenth century, Llywelyn Fawr, Dafydd ap Llywelyn, or Llywelyn the Last.
Built in typical Welsh style, it consisted of a D-shaped tower with smaller round or semi-round towers surrounding a small ward and central keep, and was built to guard the southern borders of the kingdom of Gwynedd against incursion. Its poor state of preservation today is probably the result of a combination of its exposed position and the use of poor-quality mortar. It is not known when or how Carndochan was abandoned, although unsubstantiated excavations by nineteenth-century archaeologists apparently discovered substantial amounts of ash under the ruins, suggesting the castle was either sacked or slighted.
