A motte and bailey, a causewayed road, a D-shaped enclosure, possible field systems, and what may have been a sunken hollow way all sat together on the same elevated ground. Much of it is now gone, quarried away or reclaimed into featureless pasture, which makes the 1980 description of the site feel like a record of something disappearing even as it was being written down.

The motte and bailey, the central feature of this complex, is a type of earthwork fortification introduced to Ireland following the Anglo-Norman invasion of the late twelfth century. A motte is a raised earthen mound, typically steep-sided and flat-topped, on which a wooden tower or later a stone structure would have stood; the bailey is an adjoining enclosure at ground level, used for stabling, storage, and the daily business of a small garrison or lord's household. At Kerinstown and Balrowan, the motte was described in 1980 as small and subrectangular, with the bailey lying to its south. From the causewayed entrance of the bailey, an old pathway led south-south-east toward a D-shaped enclosure defined by an earthen bank, though that bank was already interrupted by a townland boundary running north-east to south-west, and nothing remained of it on the far side of that boundary. Around the foot of the ridge to the north-east, east, and west, low banks suggested the outlines of a medieval field system, and along the eastern edge of the complex a double earthen bank with two ditches between them may have been the remnant of a hollow way, a sunken track worn down by centuries of use. Knockmant Castle and a deserted medieval settlement lie roughly 420 metres to the south-east, suggesting the ridge was part of a wider zone of medieval activity in this part of Westmeath. A preservation order was placed on the motte and bailey and its associated earthwork in 1983, though the enclosure to the south had already been lost to quarrying by that point, and subsequent aerial photography confirmed that the field systems to the north-east have since been reclaimed entirely.