Grosmont, about four miles above Skenfrith and five below Oldcastle, is placed, like the former fortress, upon the high concavity of a sharp bend of the river, about a hundred yards from its margin. Very near to it is the fine old cross church, which, having shared in the prosperity of the castle, has escaped its decay, and still remains in tolerable repair, although requiring a few subtractions and restorations at the hand of a judicious architect. The castle is composed of a court or ward of irregular plan, more or less rectangular, with projections upon the south side, the wall of which contains a space of 110 feet by 70 feet, strengthened on the south by a larger and a smaller three-quarter mural tower, having a gateway upon the east face, and on the west traces of a building exterior to the curtain wall. The north side is occupied by a hall, also exterior to, or rather replacing the line of, the curtain, three of its four walls forming a part of the exterior defences of the building. The whole is placed within a ditch of great depth, and, indeed, the earthworks generally are of so formidable a character as to make it probable that they are earlier than the present building, or than any other work in masonry. The actual platform occupied by the walls, and contained within the crest of the ditch, is about 150 feet in diameter. Outside the ditch, to the east and south, and covering the entrance of the castle, is a large demi-lune, or platform of earth, scarped towards the field, and upon which are traces of walls and a defence of the nature of a barbican. The main ditch, now traversed by a modern embankment, was evidently at one time crossed by the usual bridge, of which a part lifted. The gatehouse, if such it can be called, presents two lateral cheeks of wall, projecting on either side of the bridge, and thus forming a covered way, from each side of which a cruciform loop is directed along the ditch. The pointed vault of the entrance is broken, but there remain the ragged grooves for the portcullis, and the two holes which received the large wooden bar fastening the gate. Entering, on the right is the shell of the hall, 80 feet long by 27 feet broad, out of all proportion to the area of the defences. The floor, of timber, was laid 6 feet above the level of the court, so as to give height to a spacious basement store-room or cellar, but which, however, has a large fireplace in its east wall. The hall has windows at each end, and four in each side; but probably only the six to the east belonged to the hall, the other two lighting a withdrawing-room. The position of the fireplace on the north side seems to mark the centre of the hall.