Powys, Pen-y-cae, Brecon Beacons National Park Park. Craig-y-Nos Castle stands in the Brecon Beacons National Park Park in the Upper Swansea Valley in South Wales. Situated seventeen miles (27 Km) North of junction No 45 of the M4, on the A 4067 road to Sennybridge and Brecon, and in an area of outstanding natural beauty. The Castle has lots of accommodation, with more being added all the time, as old rooms and buildings are refurbished. En-suite rooms of various sizes and unusual shapes, including the Duplex and Bridal Suite. 10  'basic' doubles/twins, and one single room in a separate block adjoining the castle. Dormitory accommodation for up to 54 persons. Our dining and entertainment facilities cater for wedding and conference parties of all sizes. Several bars and comfortable lounges.