Old Beaupre Castle is a fortified manor house, used only as a residence, rather than a true castle, though it does have several castle-like features, including battlements, enclosed courtyards, defensive walls and an outer gatehouse. The oldest section was constructed in the early 1300s, by the Bassett family, who dwelt here almost continuously until the start of the 18th century, and was sturdily constructed in response to the sometimes unstable conditions that prevailed in this part of south Wales. The original structure was an L-shaped building of two stories, later expanded to enclose an inner courtyard, and further modified in the late 16th century by addition of another set of rooms to the north, around the middle ward, which in turn adjoins a lesser walled compound, the outer ward.
Most of the oldest part of the castle is still occupied, and up for sale as recently as 2014, but all the buildings around the middle ward are in a ruinous state, and open to the public. Two architectural highlights are the imposing outer gatehouse, and an ornate, three story porch, which leads to the great hall, one of the rooms built in the 1300s. Most of the other viewable rooms have no ceilings or roofs, but all the walls rise to the original height, and can be inspected both at ground level and partly from above, via wall walks and a first floor passage through the gatehouse. The other half of the castle is privately owned and so not accessible, but the open part has much of interest, despite being relatively small; all can be seen in about half an hour.
The manor house is named after a Norman village at this location, Beaupre, this being French for 'fair meadow', thought to be a translation of the name of the original Welsh settlement, Maes-essyllt; the new name was bestowed by the first Norman lord, from the Basset family, shortly after the conquest.
The mansion has an isolated location, not part of any village, instead surrounded by grassy fields, on the east bank of the River Thaw, 2 miles south of Cowbridge. The English Channel coast is 3.5 miles further south. The site, which is not so well signposted, is reached from St Athan Road, starting just east of the bridge over the river, at a layby with space for only a few vehicles. A 0.3 mile path crosses two fields and rises slightly to the manor, entering the outer ward via a gap in the low enclosing walls. The ruins are open during daylight hours; at the lower level the gatehouse is still fully intact, and its sturdy doors are locked at other times, presumably by owners of the adjacent farmhouse, which is linked to the ruined section in at least two places.
The south side of the outer ward is formed by the main gatehouse of the castle, of two floors plus a low-height attic (now roofless), centred at ground level on a fine double doorway between fluted pilasters, beneath the carved stone coat-of-arms of the Bassett family, dated 1586. Above here, on the first floor, are two three-light windows, while the rest of the frontage is rather plain. Steps to one side of the entrance passageway access the upper floor of the gatehouse, and then two sections of wall walk, the longest to the east, extending to a (sometimes) locked door that leads to a roofed room. Beyond the gatehouse is the middle ward, flanked by bare walls to the east, above the foundations of a terrace, and a three floor ruin to the west, a residential block built around 1540 and including several four light windows, plus fireplaces and the remains of a grand staircase.
The most impressive feature of Old Beaupre Castle is in the middle of the south side of the middle court - a decorative, Renaissance-style porch of three floors, clad with light brown sandstone that contrasts greatly with the rough, grey limestone of the adjoining walls. The ground level has the entrance passageway between two pairs of Doric-style columns; above is another Bassett coat-of-arms between two slightly smaller pairs of Ionic columns, and on the top level are four yet smaller Corinthian columns, either side of a blind window. Just west of the porch is a three light window within a bricked-up arch, site of an earlier gatehouse. The passageway through the porch, whose brick-built sides bear inscriptions from visitors in the preceding centuries (the earliest seems to be 1719), leads to the ground floor great hall, amongst the oldest sections of the castle, complete with original fireplace adorned with armorial shields. The west side of the hall has doorways to the large residential block and to another room, while to the east is a steep staircase to a first floor, square-shaped room with modern floor (and ceiling), sometimes locked, and linking with the residential farmhouse beyond.