A few buttresses scattered on a hillside in Thrunton Woods. Most notable for one of the finest pieces of hard climbing in Northumberland, 'The Young' 8a+/E8 - NMC Bouldering Guide p. 422, but some other short leadable routes on good rock.
The crag is hard to find with no path to it and appalling directions in the NMC guide. Follow the tracks from the parking as suggested until an unmentioned t-junction is reached. Either right and guess how to get over the top of Castle Hill to the crag, or turn left then right onto the forest track, bear rightwards and bash diagonally right up the hillside to the crag. The UKC map seems accurate.