Built in the first decade of the 19th century as part of an ambitious chain of over 80 signal stations stretching from Dublin Bay to Malin Head, this tower once stood guard against the threat of French invasion. Today, only subtle traces remain: a grassy rectangular enclosure measuring about 26 by 17.5 metres, marked on old maps as an ‘old watchtower’, and a square depression roughly 9.7 metres across that likely marks where the tower’s semi-basement once lay. Some have suggested the enclosure might be the remains of an ancient ecclesiastical site called ‘Teach Eoin’, though there’s no evidence to support a pre-1700 date.

The signal tower formed a vital link in a communication chain that could relay warnings along Ireland’s entire coastline using naval signal posts. From this low-lying spot, 26 metres above sea level, operators could see Carrigan Head signal tower nearly 17 kilometres to the northwest in good weather, whilst Killcologue Point tower, 11 kilometres south, has since been demolished. When Napoleon’s threat diminished by the mid-1810s, the entire system was abandoned, and much of St John’s Point tower’s masonry likely found new life in the nearby lighthouse complex, built around 260 metres to the west-southwest.

The site remains rich with military history from different eras. A well-preserved World War II lookout post stands 112 metres northeast of the old tower site, whilst the overgrown remains of an ‘Eire 70’ sign, painted to warn Allied aircraft of neutral Irish territory during the war, can still be found near the peninsula’s tip. These layers of defensive architecture, from Napoleonic watchtower to wartime observation post, reveal how this windswept corner of Donegal has long served as Ireland’s sentinel, keeping watch over the wild Atlantic approaches.