Magnificent Medieval Castle in spectacular defensive situation on vertical cliffs above the River Wye, aligned predominantly E/W, over rising ground. Constructed of stone, rubble and dressed. Main entrance at E through the Outer Gatehouse comprising twin round towers with battered base, cruciform and plain arrow slits at 3 levels, later square-headed windows with mullions and trefoil-headed tracery; central double arched gateway with portcullis slots, remains of barbican, murder holes, metal-reinforced wooden double doors; high detached arch above. Adjacent to left (S) is a stretch of battered curtain wall standing almost to battlement level with arrow loops. This adjoins Marten's tower, D-shaped in plan with rectangular corner turrets, one with high E facing arched window, deep spur buttresses, deep arrow loops at 3 levels and trefoil-headed lancets, deep coped battlements with arrow slits, crowned by eroded stone figures (C14); also a later 2-light Tudor window. Curtain wall continues at a right angle, slightly curved and following the crest; signs in the masonry of alteration and rebuilding, including a blocked arch; two wide buttresses and range of rectangular cannon slots along the top; this forms the S wall of the lower bailey. At the junction between this and the S wall of the middle bailey is a round tower with battered base, 3 storeys, battlements, arrow slits. Further to W a second D-plan tower, with battered base, battlements, arrow slits. Curtain wall continues to adjoin the rectangular Great Tower; outer wall of 5 bays separated by pilasters of large square stone blocks; originally no windows, one C13 insertion. Curtain wall continues from upper end enclosing the upper bailey extending to the outer face of the Corner Tower with ashlar quoins standing to battlement height with cruciform arrow slits, 2 round-arched windows at wall-top level and blocked arch to plinth, low large blocked arrow loop; this is the top of the upper bailey. At the W end comes the Barbican complex, comprising a tall circular corner tower on a rocky outcrop, with cruciform arrow slits at 3 levels and all angles. The wall between tower and barbican is curved rising from bare rock, intact to battlements and incorporating arrow slits. The tall Barbican Tower itself, also rising from high bare rock, stands in front of the W gateway; sides of tower are battered for 3/4 of their height; three large arrow slits below a corbel table beneath the battlements; tall outer arch (remodelled C20); pointed inner arch with portcullis slots within the pointed tunnel vault; heavy double doors. The N side of the castle complex standing directly on the river cliffs can only be seen from a distance but follows the same sequence except at the E lower end where the outer wall of the great hall, kitchen and service block and chamber block adjoin the E side of the outer gatehouse.