South Light, Rue Point, Rathlin Island, Co. Antrim

South Light, also known as Rue Point Lighthouse, is a four-stage octagonal concrete lighthouse constructed in 1921. It stands 35 feet high on a low concrete platform cast directly onto the rocky foreshore at the southeastern tip of Rue Point, the southernmost extremity of Rathlin Island.

The tower is accessed via a grassy and concrete footpath running down the eastern side of the island from the end of the public road. The final approach to the lighthouse crosses the rocks on a slightly raised concrete footpath, fitted with a modern plastic and wire handrail supported on regularly-spaced painted original metal posts.

Each of the four stages of the tower is delineated by a shallow string course and painted alternately black and white, creating a distinctive banded effect. The base of the tower is slightly advanced and painted black. The flat concrete roof is surrounded by a low parapet over a plain cornice and is fitted with a two-bar metal handrail. Small rectangular openings in the parapet serve as rainwater run-off points.

An omni-directional light mounted centrally on the roof rises 17 feet with no protective lantern. It produces two white flashes every five seconds and has a range of 14 nautical miles (16.1 miles). A small radio aerial sits beside it.

Access to the interior is via a vertical metal ladder on the north side of the tower, leading to a cantilevered concrete platform in front of a sheeted timber door at stage 2 level (with stage 1 being ground floor). The door has a small louvred ventilator and is flanked by projecting curved metal handrails. The top of the ladder can be pulled out to facilitate access to the platform. Above the doorway is a window opening at stage 4 level with slightly advanced jambs and horizontal stucco head, with the string course serving as its cill. Identical window openings exist on the east, south and west sides at stage 4 level, all of which have been blanked off and painted black.

Just southeast of the lighthouse is a low concrete platform which originally mounted a fog gun. This platform was reused between 1917 and 1921 to support a temporary light whilst the present lighthouse was being constructed.

A modern single-storey standby block housing a back-up electricity generator sits beside the access track. This building is aligned northeast to southwest with a pitched roof, painted eaves boards, and boxed eaves with no rainwater goods. It has cement-rendered walls, a flat-headed painted tongue-and-groove door to the northeast gable, and a modern one-pane window with shallow concrete cill on the northwest elevation. The southwest gable is blank. A galvanised metal ventilation duct and pipe project from its southeast elevation. Concrete floor platforms in the vicinity indicate the former positions of wooden huts, one of which housed the keepers until the site was demanned in the mid-1900s. The other housed two diesel engines for generating electricity.