to limit access to Howth Harbour, and to observe and partly control usage of the anchorage area northwest of the Eye. The tower is built of rubble coated with rendering, with some brickwork, at least in the domed roof area, and a few pieces of cut limestone. It features both a plinth and a machicolation, a single entrance on its southern face, and three other small openings. The interior was, and largely remains, lime-washed. There was a wooden floor at the first-floor level, to which the raised door gave access; this has subsequently been removed. The undercroft is divided in three by rubble walls, and there is an iron storage chest there. The tower originally occupied a designated section of the island, with boundary-marking stones, and was sited near the island's spring. The tower was rarely occupied, which contributed to poor maintenance, but there was a period during which it was a base, perhaps seasonal, for an early modern customs patrol body, the Preventative Water Guard. The Board of Ordnance having failed to rent out the tower, it was sold to the Lords of Howth in 1909, and passed to the Gaisford-St Lawrence family soon after, when the direct family line ended. It is believed to be structurally sound but is not actively maintained or in any official use. Its entrance, 5 metres above ground level, can be accessed by a rope that hangs down from the window. Jurisdiction, status and management Ireland's Eye lies within the historic County Dublin, and is now in the jurisdiction of Fingal County Council. It was previously governed by Dublin County Council, having been moved from the jurisdiction of the city of Dublin as part of a transfer encompassing Howth, Sutton, Baldoyle and Kilbarrack, and, explicitly, Ireland's Eye, and having in turn previously moved from the county administration. It is a townland in its own right, with a registered area of , in turn within the civil parish of Howth, and the barony of Coolock. Statuses and designations The island, its rocks and the islet of Thulla, and the surrounding waters, form both a Special Area of Conservation (SAC), based on two qualifying interests (perennial vegetation of stony banks and vegetated sea cliffs of the Atlantic and Baltic coasts), and a Special Protection Area (SPA). They are also within the large Rockabill to Dalkey Island SAC. The island is a proposed Natural Heritage Area