The site consists of a circular, grass-covered mound measuring approximately 9 metres across at its summit and expanding to 24 metres at its base from northwest to southeast. Standing between 2.6 and 3 metres high, the mound shows signs of damage on its summit and is now partly covered by trees. A rounded fosse, or defensive ditch, encircles the structure, measuring about 10 metres wide at the top on the northwestern side with an external depth of half a metre.

What makes this site particularly interesting is the presence of a crescent-shaped bailey extending to the northwest of the main mound. This slightly raised, grass-covered platform measures roughly 34 metres from northwest to southeast and 31 metres from northeast to southwest, though it rises only 20 to 50 centimetres above the surrounding ground. The bailey is defined by faint traces of an earthen bank, approximately 5.4 metres wide at its base, which stands about 20 centimetres high on the interior side and 50 centimetres on the exterior.

This type of fortification, commonly known as a motte-and-bailey, represents one of the most widespread forms of medieval castle construction in Ireland, typically dating from the Anglo-Norman period. The motte provided a defensible position for a wooden tower or keep, whilst the bailey served as an enclosed courtyard for additional buildings and activities. Though time and weather have softened its once-imposing profile, the earthwork at Killadden remains a tangible connection to the medieval landscape of County Meath.