There is a tower house at the centre, and around it the footprint of a bawn, the enclosed courtyard that typically surrounded such structures, defined by a stone wall nearly two metres thick. But the bawn at Ballyknock carries an older outline within it. Its circular shape, roughly forty metres in diameter, is not the usual form for a bawn, which more commonly follows a square or rectangular plan. The circularity here points to something earlier.

The working interpretation is that whoever built the bawn did not start from scratch. Instead, they appear to have followed the curve of a pre-existing ringfort, a type of enclosed farmstead common across Ireland from the early medieval period, typically defined by earthen banks or ditches arranged in a rough circle. At Ballyknock, that original enclosing element was absorbed into the later medieval stonework, its circuit preserved in the arc of the bawn wall even as the ringfort itself disappeared beneath it. No surface trace of the earlier structure survives independently; the ringfort is essentially readable only as a ghost embedded in what replaced it. The hillock itself would have made the site attractive across both periods, offering visibility and a degree of natural elevation in an otherwise unremarkable landscape.