A natural knoll that has been physically modified and known locally as Henni Castle or Hennaborough. There has been speculation since at least the early 19th century that the mound and its supposed earthworks represent the site of a Saxon encampment from which the men of Devon emerged to defeat the Danish at the battle of 'Arx Cynuit'. There are, however, strong arguments for other locations. (Green 2010)

About half-way down the hill, traces of a ditch can be seen, the circuit of which is 250 meters. A loose stone wall 2 meters high, 100 meters long is close by and partly supports a low bank. Herringbone structure, characteristically Saxon. A Saxon earthwork - the corresponding Danish fortification is at Godborough. (Rogers 1948)

The earthwork remains known as Kenwith Castle comprise a natural knoll which is fortified on the upper slope by a single rampart with a simple entrance at the west end. The site has also been known as Henni Castle or Henniborough Castle within the local area. The rampart runs away to the east where there may have been a former entrance; Kenwith Farm interferes with it at the easternmost point. A disused quarry cuts into the south-west base of the hill. The rampart has the appearance of ledge and terrace on oval shaped mound. The top is relatively level and the enclosure is circa 50 metres running east-west. There is an old pit at the east end and there was a wooded platform to the west but this no longer remains. (PastScape)

Higham writes very doubtful with no convincing documentary or archaeological evidence. A watching brief on groundworks at Kenwith Castle Residential Home found 'only a few sherds of medieval ware' although the area examined was some distance from the suggested medieval site. The actual scarping of the hilltop is suggested as C18 ornamental terracing. The house currently bearing the name Kenwith Castle dates back to the C18 and was built in a castellated gothick style