There are three entrances to the outer ward, the chief being a square gate tower in the west wall which was defended by a portcullis. There is another entrance on the north, as well as a doorway opening on the river.
The chief buildings are situated near the water’s edge. They consist of the great hall which is 75 feet long by 37 feet in breadth. It is lighted by three windows of rough masonry in its south wall and by one on the west, with fifteenth-century “ogee” heads inserted in the older workmanship.
The doorway on the east opens to the river. The chief entrance and porch were on the north side. The base of one of the sandstone jambs remains, showing it to have been of thirteenth century date. The walls are 3 feet thick, and the roof, which had a very high gable, was supported by four pillars.
At the eastern end are the buttery and smaller offices, while separated from them by a passage is the ruined kitchen (45 feet by 19 feet), which contains the remains of an oven and also a small well of river water. A curtain wall running west, connects these building with a fine oblong, two-storey structure, 56 feet by 31 feet, which is remarkable, inasmuch as the walls of the top storey are thicker than those below, the extra width being supported by projecting stones. The top room, which has loops splayed for archery, was reached by an exterior stone stair. The floor was supported on beams, and the lower room seems to have been used as a stable.
Adjoining the building is a small square tower, which projects into the river that flows under it through an archway in the basement. A wall connects this tower with the gateway.
The inner ward is now reached by a small wooden bridge. The gate tower is connected with the S.E. angle of the keep by a thick curved curtain with an embrasured and looped parapet. A turret protected the juncture of the outer and inner walls. A semicircular tower also projects from the boundary wall on the left of the inner court. It was loopholed, and divided into two storeys.
The keep, which is in the inner court, is about 40 feet square and 67 feet high. Only the north wall and the portions adjoining it remain at their original height. The side next the river is entirely broken down, tradition saying it was destroyed with cannon in Cromwell’s time from the opposite hill. The angles of the remaining wall are crowned with turrets.
The doorway leading to the vaults being of later date than the rest it is supposed they were of more recent insertion. One of the dungeons seems to have been used as a prison. It is lighted by a loop of peculiar construction.
A staircase leads to the chief apartments, and a well of river water is within the walls. The height of the keep seems to have had a third added to it after its original construction as is shown by the old weather-tabling of the roof. The present building was divided into three storeys above the ground floor, which was vaulted. The stairway was in the thickness of the west wall. Small cells occupy the projecting portions at the angles.
From the objects that have been found in the moat which surrounds the keep, it has been thought likely that it occupies the site of a rath, as some of the relics are of much anterior date to the Norman Conquest. The fortress is supposed to have been formerly a stronghold of the O’Donovans until they were dispossessed by the invaders.