Small defensive earthwork of possible Iron Age date on the summit of Castle Hill. The earthwork is accessible from a public footpath from Glasshouse, and from the Wysis Way path that skirts the north side of the hill. A short distance to the west stands the instantly recognisable May Hill, a landmark that can be seen from many miles around and from many directions.
It is however possible that the earthwork is a motte site of Saxon/early Norman date. I have found no record of any excavation that would help to establish the date more accurately.