This impressive earthwork consists of a circular mound measuring 21 metres east to west and 27 metres north to south at its base, rising to a height of 5 metres with a flat top spanning 8 metres across. The waterlogged ground along its southern edge suggests the original builders may have dug a defensive ditch, or fosse, around the structure; a common feature of medieval fortifications in Ireland.

Today, a laneway runs along the western base of the mound, accompanied by a curious curved earthen bank about a metre high. This secondary feature, topped with a well-established line of mature trees, stretches for roughly 16 metres and adds another layer of interest to the site. The strategic positioning of the moat becomes clear when you take in the panoramic views from its summit; on a clear day, you can see from Lambay Island to the east, across to Howth and the Dublin Mountains to the south, and as far as County Kildare to the southwest.

While the exact date of construction remains uncertain, the mound has clearly seen better days. Livestock have damaged portions of the earthwork over the years, leaving their mark on what was likely once a more pristine defensive structure. Historical surveys by Morris in 1939 and Healy in 1975 documented the site's condition, helping preserve knowledge of this intriguing piece of Dublin's medieval landscape for future generations.