A mound at the east end of Bellingham is all that remains of the former motte and bailey castle. It was probably built in the 12th century by the Bellingham family and is likely to have been replaced by a stone castle in the 13th century. The existence of a castle here is suggested by documentary evidence which reports that William de Bellingham, sheriff of Tynedale and forester of Tynedale under the king of Scotland, had his seat at Bellingham. The mound is topped by a smaller mound and, because the top of this feature is quite small, doubt has been expressed about the form of the castle if it was situated here; it has also been suggested that the whole mound is a natural feature.