The two-storey square tower, built from roughly coursed rubble stone masonry, was constructed as part of an extensive coastal defence network during the Napoleonic Wars. It formed one link in a chain of over 80 signal stations that stretched around Ireland’s coast from Dublin Bay to Malin Head, designed to warn of approaching French invasion fleets. The tower was positioned to maintain visual contact with its neighbours; the now-demolished signal tower at Bloody Foreland, 14.2 kilometres to the north-northeast, and the still-standing tower at Crohy Head, 13.2 kilometres to the south-southwest, which remains visible in clear weather.

Despite missing some defensive features like the machicolation over the first-floor doorway and the bartizans that once crowned its rear corners, the tower survives remarkably intact at nearly 12 metres high. The structure reveals fascinating defensive architecture typical of the period: the first-floor entrance, originally accessed by retractable ladder, prevented easy enemy access, whilst the interior featured a semi-basement, ground floor with split-mezzanine level, first floor, and low attic space leading to the flat roof. Pairs of square-headed windows punctuate the northeast and southwest walls, whilst fireplaces flanked by alcoves warm the southeast wall on both main floors. An ingenious square-sectioned drainage channel runs down the eastern corner, originally carrying rainwater from the roof to storage barrels in the semi-basement; a practical solution for water supply in this isolated location.

After the French threat diminished in the mid-1810s and the signal system was abandoned, the tower found new purpose as a Coast Guard Station later in the 19th century. During this period, a rectangular enclosure was added immediately west of the tower, though no traces remain today save for a small concrete pillar or tank that may date from this secondary occupation. The site lies about 1.5 kilometres northeast of a group of holy wells in a graveyard on nearby Cruit Island, adding another layer of historical significance to this windswept corner of Donegal where military strategy, maritime surveillance, and ancient sacred sites converge.