Overview
Rotten Island Lighthouse sits on a small, wind‑swept island at the south‑east corner of the entrance to Killybegs Harbour in County Donegal. Built between 1837 and 1838, the freestanding two‑stage tower is constructed from ashlar granite and painted white, making it a striking landmark against the Atlantic sky. Operated by the Commissioners of Irish Lights, the lighthouse continues to serve as a harbour light, marking the safe passage from St John’s Point to the inner channel and the anchorage within the harbour.
The lighthouse is not open to the public, but its silhouette can be admired from the water on boat trips, from the Killybegs waterfront, or from the surrounding cliffs. Its historic fabric, robust boundary walls, and the story of its construction make it a compelling stop on any Donegal coastal itinerary.
Name and Meaning
The Irish name An tOileán Bréan translates literally as “the stinking island”. Early English writers rendered this as “Rotten Island”. The exact reason for the name is uncertain – local folklore points to the smell of seaweed or fish off‑cuts from Killybegs’ busy fishing fleet, while some suggest a Viking‑era burial or a historic plague pit. Whatever the origin, the name reflects the island’s rugged, untamed character.
History
The need for a light on Rotten Island was first raised in 1832 when the Inspecting Commander of the Coastguard, Mr Drury, wrote to the Ballast Board recommending a beacon on Drumanoo Point. Inspector George Halpin, a prolific lighthouse designer, argued for Rotten Island instead. The Board approved the scheme on 7 November 1833 and secured statutory sanction from Trinity House shortly thereafter.
Construction was overseen by the Board’s own workers under Halpin’s inspection. The tower, a tapering circular plan with a faceted glass and metal lantern, was completed at a cost of £8,850 14s 10d – a considerable sum for the era. Tragedy struck during the build: three men drowned on 15 September 1836 when their boat capsized returning from work on the rock.
The light was first exhibited on 1 September 1838, using a fixed white catoptric third‑order lens positioned 66 ft above high water, visible for 12 nautical miles in clear weather. In 1910 the fixed light was replaced by a fifth‑order dioptric lens flashing once every three seconds, and the character was altered again in 1965 to a flash every four seconds.
Automation arrived on 7 January 1959, when the original revolving mechanism and paraffin burner were replaced by a fourth‑order cylindric refractor lens powered by dissolved acetylene. The light was finally electrified on 1 February 1963, boosting its candlepower to 13 000 white and 2 600 red. An automatic battery backup and optional acetylene standby ensure continuous operation should the mains supply fail.
The lighthouse and its ancillary keeper’s house are recorded on the [Buildings of Ireland] database (Reg No 40909715) as a protected structure of architectural, social and technical interest.
What to See & Do
While the tower itself is not accessible, visitors can enjoy several visual experiences:
- Coastal viewpoints – The cliffs and headlands around Carntullagh Head offer panoramic views of the lighthouse against the sea. Photographers will appreciate the contrast of the white tower with the dark basaltic shoreline.
- Boat tours – Local operators in Killybegs run short trips that bring you within a few metres of the island, allowing a close‑up look at the lantern, metal walkway, and the imposing rubble‑stone boundary wall. Tours typically run from May to October, cost €15‑€30 per person and last about 20 minutes.
- Heritage walk – A short walk through Killybegs Harbour’s historic fishing quarter provides context for the lighthouse’s role in protecting the town’s fleet for nearly two centuries.
- Wildlife spotting – The island and surrounding waters attract gulls, razorbills and occasional puffins. Seals are often seen on the rock outcrops, especially in the early morning.
- Photography – Sunrise and sunset give the tower a warm glow; the best light is usually just after the tide turns, when the sea is calmer.
The lighthouse’s technical specifications are of interest to maritime enthusiasts:
| Feature | Detail |
|---|---|
| Height of tower | 14 m |
| Height of light (MHWS) | 20 m |
| Light character | Fl WR 4 s (one flash every four seconds, white and red sectors) |
| Range | White 15 nm, Red 11 nm |
| Sector bearings | W225°‑008° (113°), R008°‑039° (31°), W039°‑208° (169°) |
| Coordinates | 54.61465 N, ‑8.44058 W |
Practical Information
- Access – The island is uninhabited and the lighthouse is not open for interior tours. The most practical way to view it is from a boat departing Killybegs Harbour or from designated coastal viewpoints.
- Parking – Free parking is available in the Killybegs harbour area; a small fee may apply during peak season. From the car park, a short 10‑minute walk leads to the waterfront where boat operators pick up passengers.
- Boat tours – Several local operators run scheduled trips (May‑October). Prices range from €15 to €30 per person; advance booking is recommended in summer.
- Public transport – Bus Éireann and Local Link services connect Donegal Town and Letterkenny with Killybegs. From the Killybegs bus stop, it is a 10‑15 minute walk to the harbour.
- Safety – The island is exposed to Atlantic swells; visitors should heed local advice regarding sea conditions, especially when arranging boat trips.
- Website – For up‑to‑date information on boat tours and the Commissioners of Irish Lights, visit the official page: Rotten Island Lighthouse – Irish Lights.
Nearby Attractions
Rotten Island forms part of a rich maritime landscape. While you’re in the area, consider adding these stops to your itinerary:
- Arranmore Island – Lighthouse and Scenic Trail – A short ferry ride from Killybegs brings you to Ireland’s largest offshore island, where a historic lighthouse and coastal paths await. (Arranmore)
- St John’s Point Lighthouse – Located on the opposite side of the harbour entrance, this smaller beacon offers another perspective on Donegal Bay’s navigation network.
- Carntullagh Head – The headland provides dramatic cliff‑top walks and excellent photo opportunities of Rotten Island.
- Killybegs Harbour – Explore the bustling fishing port, sample fresh seafood, and learn about the town’s maritime heritage at the local museum.
Rotten Island Lighthouse stands as a testament to 19th‑century engineering, the dedication of its builders, and the ongoing importance of maritime safety in Donegal Bay. Whether you’re a history buff, a photography enthusiast, or simply seeking a striking coastal scene, the lighthouse adds a compelling chapter to a Donegal adventure.