Dolwyddelan Castle is a Welsh castle located near Dolwyddelan in Conwy County Borough in North Wales. It is thought to have been built in the early 13th century by Llywelyn the Great, Prince of Gwynedd and North Wales. Though the castle was then only one tower with two floors, a second tower was built in the late 13th century and a third floor was added to the first during the late 15th century repairs.