The site of the castle is on private land.
Kirkby Malzeard was one of the less important estates belonging to the Mowbray family, who had castles and manors at Epworth, Burton-in-Lonsdale and Thirsk as well.
Although it’s unclear when the castle was built, records show that it was destroyed after the rebellion of 1173-4.
Roger de Mowbray was at the height of his power, and joined in a conspiracy with the Bishop of Durham, to place Prince Henry on the throne. The castle was besieged and taken by Geoffery Plantaganet (Bishop elect of Lincoln and an illegitimate son of the King Henry l) and the Archbishop of York. The rebellion collapsed, and although Roger de Mowbray surrendered and received a pardon, his castles at Thirsk and Kirkby were dismantled.
The castle was the seat of manorial administration for a very extensive area, and it seems that the original castle was of earth and timber construction. As there have been carved stones/fragments found on the site, some of which had an ecclesiastical origin, it is believed that these are of a later date, and a small manor house could have been built within the earthworks of the original castle.
In the early nineteenth century the remains were quite extensive, and Whitaker, in his History of Richmondshire, described the castle as follows:
Its foundations and the gigantic earthwork which surrounded it; are still very conspicuous at the east end of the Churchyard; and the groundwork of the great hall, the chapel, and other apartments within the bailey, have been disclosed, by digging out stone for the use of a neighbouring house, where several Norman capitals and bases have been discovered. The situation is advantageous, having a steep declivity descending to Kesbeck, which appears to have been separated into a pool on the North; while on the more accessible sides art has abundantly supplied what nature had witholden. The whole circuit was an oval enclosing a single area, without a keep, and the principal buildings were placed, for the purpose of admitting light and sunshine, nearly against the North wall of the bailey and towards the East end. In this line have been three principal apartments, of which that on the West seems to have been the kitchen; next, the great hall; and lastly, a smaller apartment, by the door which a Norman base and the stump of a cross have been dug up. This seems to have been the chapel. Another large oblong apartment, rather Southward from this line, may have been the stables. The whole area scarcely exceeds half an acre.
Many years ago, the then owner of Mowbray House, Col. Hon. A. M. Cathcart employed some workmen to make some holes to place posts in. Whilst making one particularly deep hole, the iron bar being used slipped and fell into the hole. This may be the well that was later excavated, and where arrow-heads, sling bolts and other items were found.
All that can be now seen are some small mounds, and a stone cross bearing the words ‘Site of Mowbray Castle, destroyed by the order of Henry ll, 1173’.
The site of the castle is on private land.