The huge rampart of Craig Arthur looms impressively over the upper end of the Eglwyseg Valley. At around 40m it is by far the tallest of all the cliffs along the escarpment. The quality and length of the routes - both trad and sport - makes it a crag of national importance, with a number being multi-pitch offerings, adding a welcome dimension to the area that is otherwise dominated by shorter single-pitch climbs. The crag is mostly vertical but frequently crossed by horizontal bands of overhangs, especially in its upper reaches, making for some very exciting finishes. The rock is mainly composed of good-quality weathered white and grey sheets, seamed with some strong crack and flake lines. Some of the less frequented lines still have loose sections and can be a little vegetated. The crag's location is both spectacular and beautiful with expansive views above a base clear of vegetation. Its scree slope shelves away steeply making the exposure felt from the first moves on most routes. Many of the routes, both trad and sport, rely on fixed protection from pegs, threads and bolts although a full rack and double ropes are also required for the trad lines. A clip-stick may be useful as a number of the initial bolts on the sport climbs are fairly high.