The rebuilt castle featured a hall-keep, an uncommon design in English castles; built of stone, this was a three-storied structure long, wide and high. Internally the keep was divided to form a long hall and a solar and was lit by large, rounded windows. The keep had architectural similarities to various nearby castles in the region, but in particular to those at Middleham and Outhgill. A ditch formed an inner defensive bailey around the keep, with the ramparts of the old fort forming a larger, outer bailey. A mill, then an essential part of any castle, was built by the River Greta to supply flour for the garrison . The village of Bowes was built after the castle and formed a planned site running up to the castle, complete with a church and a market place; this form of planned village is again unusual in England.