Chirk Castle, occupied virtually continuously as a castle and stately home for almost 700 years, sits on a hilltop with its best views over the Ceiriog valley to the south. The successor to two known mottes in the area, it was probably built by Roger Mortimer, of the powerful Marcher family, who was granted the area by Edward I after the Welsh defeat in 1282. He was almost certainly given royal assistance in its design and construction, and its similarities to Beaumaris suggest that work may have started as late as 1295, perhaps in response to the Welsh rising of 1294.
The castle may have originally been envisaged as a rectangular enclosure with towers at the corners and halfway along each side. If so, only the northern half of the design survives, stopping beyond the central towers on the east and west. The simple gate through the eastern part of the north wall is probably original. Additional outer defences were dismantled during later landscaping.
The spirit of the 14th century structure is preserved in the Adam's Tower (near the well on the south-west), which has a magnificent dungeon on two levels and a number of upper rooms clearly showing the 5m-thick walls. Two of them contain 'murder holes', through which material could be poured on to anyone trying to batter or burn down the doors below. This tower, like the others, was originally at least one storey higher, the upper parts probably being removed after the Civil War bombardment of 1659.
The south curtain was completed on the present line early in the 15th century, under Thomas, earl of Arundel, probably against Owain Glyndwr's forces, who had strong local support. The chapel in the present south-east corner, possibly begun in the later 14th century, and the adjoining hall are the earliest surviving stone rooms outside the towers. Timber structures probably stood against the other walls.