The ruined medieval castle at Penmark, Vale of Glamorgan, is unusual for being unrestored, publicly accessible and still having some significant structures, as most such places are either managed and partially restored, or have very little remaining. There is however a similarly abandoned and overgrown ruin on public land just two miles west, the larger East Orchard Castle.
Penmark is a quiet village on a ridge between the River Waycock and a smaller, unnamed drainage, both tributaries of the River Kenson, which flows past a short distance west, and both form relatively deep and narrow valleys, hence the settlement has good natural protection. The castle was built towards the end of the 13th century by the baronial de Umfraville family, and at its peak consisted of an oval-shaped inner bailey 210 feet across enclosed by curtain walls with various rooms and towers at intervals, adjoining an outer bailey on the west side. The ruins are only fragmentary - a section of the western wall leading to a turret and a two story tower, plus part of a dovecote and overgrown rubble piles from other rooms - but the site is still interesting, and quite evocative. Views are somewhat limited because of the vegetation, as the ruins are mostly covered by ivy, and the woodland in the river valley conceals the castle from the north.
Penmark lies along an undesignated country road just north of the B4265, close to Cardiff Airport. The castle is not signposted though easily reached, by walking 150 feet down a farm track and over a gate into the field occupying the site of the outer bailey, beside the local parish church. Parking is available along the road, at the church entrance.
The north side of the field, bordering the Waycock river valley, is lined by a wall of relatively recent construction, leading the remains of a 13th century dovecote at the northwest corner. The other end of the wall connects with the main surviving section of the castle, which consists of a 130 foot length of the west curtain wall, the northern part of which meets a rectangular latrine turret beside a D-shaped corner tower. Beyond here, the land slopes steeply down by 60 feet to the river. Other, overgrown masonry remains can just be discerned to the east, on the far side of the inner bailey, including further wall sections and parts of three rectangular rooms. The west wall also incorporates the ruins of a barn, which from the outside at least resembles the rest of the ruin but is in fact a much later building, put up in the 18th century, using material from the now vanished sections of the surrounding walls. The barn had a pair of doors, one cut through the outer castle wall. The northwest tower is still about 25 feet tall, with two arrowloops on the ground floor and two on the upper floor, plus two doorways, both once leading to walkways on top of the curtain walls. On the northwest side of the tower are the remains of another turret, or annexe (a 14th century addition), also originally of two stories, while to the south is the latrine turret, the lower section of which is formed of a vaulted, windowless enclosure, mostly contained within the thickness of the curtain wall.
It is believed that a fortification was first constructed at Penmark by the de Umfraville family in the early 12th century, either by the first known representative Gilbert de Umfraville, or his successor Robert. The (presumed) timber and earthwork castle was rebuilt in stone about 150 years later, the first definite reference being in 1307, and it seems to have been inhabited until at least the early 1400s, by which time the building had been transferred by marriage to the St John family. They later moved to a newer and larger castle at nearby Fonmon, and although Penmark Castle was subsequently occupied by several tenants, it had become ruined by the 17th century. Much was dismantled over the next hundred years and the stones reused, for the barn and for other projects in the village.