The most visible is the least ancient: a Second World War lookout post, LOP 53, unusual among its type in being surrounded by a low rubble stone enclosure. A short distance to its south, the number 53 is picked out on the hillside in loose stone, the surviving fragment of what was once an "Eire 53" sign. These signs were laid out on Irish coastlines during the Emergency to identify neutral territory to aircraft overhead. The enclosure wall of the lookout post may well incorporate masonry stripped from an older structure on the same summit, a signal tower built around 1806 whose stones were long ago carted away for field walls and buildings elsewhere. What remains of that earlier tower amounts to two grassed-over sections of walling forming a right angle, their inner faces still showing intact stonework, the whole barely thirty centimetres high.

The signal tower at Bunowen was one of more than eighty constructed by the British Board of Ordnance in the first decade of the nineteenth century, forming a continuous coastal chain from Dublin Bay clockwise around the island to Malin Head in County Donegal. Its purpose was to relay warnings of an approaching French invasion fleet using naval signal posts. The system was abandoned by the mid-1810s once the threat had receded, and the towers were left to whatever fate local demand for building stone could arrange. The Bunowen tower was originally two storeys, square in plan, with internal dimensions of roughly 4.25 metres on each side. Its nearest neighbours in the chain, at Ard Castle Hill to the south-east and Cleggan Hill to the north, have fared no better; both are demolished or reduced to low ruins, and neither is now visible from Bunowen Hill. About 23 metres to the north-west of the signal tower site stand the fragmentary remains of what appears to have been a folly, a purely decorative or whimsical structure with no defensive or functional purpose, erected by the Geoghegan family, later the O'Neills, of nearby Bunowen Castle. The castle itself, a ruinous castellated former country house, sits roughly 325 metres to the north-east. Follies of this kind were fashionable across Irish estates during the late eighteenth and early nineteenth centuries, and the corner walling and a splayed window reveal are all that survive here.

The hilltop also sits in older company. A medieval parish church lies around 164 metres to the east, and roughly 242 metres to the west is a holy well recorded on the Ordnance Survey's first edition six-inch map, surveyed around 1837 to 1838, under the name "Well of the Seven Daughters". The name alone suggests a layer of local tradition that the map-makers noted but did not explain.