Overview
Lough Swilly is one of only three true glacial fjords in Ireland – with Carlingford Lough and Killary Harbour – a deep sea inlet that splits the Inishowen Peninsula from the Fanad Peninsula in north Donegal. Its Irish name, Loch Súilí, means ‘lake of eyes’, though ‘lake of shadows’ is the version you’ll hear locally.
The shelter and depth that make it a fjord also made it a naval prize. A ring of Napoleonic forts still guards the shore, a gold-laden liner lies wrecked at its mouth, and it was from here, at Rathmullan, that the Gaelic earls sailed into exile in 1607. The reclaimed wetlands at the southern end are now a Special Area of Conservation and one of the country’s best winter bird sites.
A landscape shaped by history
The human story here runs deep. Archaeologists have found shell middens dating to around 7000 BC, and the Iron Age fort of Grianán Ailigh still crowns the hill above the southern shore. The lough’s strategic weight showed itself in 1607, when Hugh O’Neill and Rory O’Donnell sailed from Rathmullan in the Flight of the Earls, ending the old Gaelic order.
By the Napoleonic era, the fjord’s depth and shelter made it a prized anchorage. Between about 1800 and 1820 the British built a ring of defences – six Martello towers and several larger forts, among them Fort Dunree, Lenan Head, Ned’s Point, Inch Fort, Knockalla and Macamish Point – to keep the French out. The sea took its own toll: the frigate HMS Saldanha was wrecked here on 4 December 1811 with the loss of all 253 crew, some 200 of whom washed ashore. The lough later held part of the Grand Fleet in the First World War and stayed a British Treaty Port until 1938, when Fort Dunree was handed over to the Irish state.
What to see & do
Wildlife & birdwatching
The wetlands and salt meadows around the southern lough turn into a winter sanctuary. From November to February, more than 4,000 whooper swans gather alongside thousands of Greenland white-fronted, barnacle, greylag and brent geese. The Inch Levels Wildfowl Reserve, about 8 km south of Buncrana, is the best vantage point for watching them without pushing the flocks off. Out in the deeper channels, grey seals, bottlenose dolphins and harbour porpoises turn up, especially on calm mornings.
Historic forts & museums
- Fort Dunree – now a military and wildlife museum, with Napoleonic artillery, First World War memorabilia and exhibits on the lough’s marine life. If you only have time for one stop, make it this one.
- Lenan Head Fort – one of the larger coastal forts built to guard the entrance, later fitted with heavy guns; the setting and the view across the mouth are the draw.
- Inch Fort & Ned’s Point – accessible ruins that trace coastal defence from the early 1800s through the World Wars.
Diving the SS Laurentic
Off the mouth of the lough lies the wreck of the SS Laurentic, a British liner requisitioned as a troopship and sunk by a German mine in January 1917 while carrying 3,211 gold ingots. All but 20 were recovered in one of the great salvage operations of the century. The wreck sits at around 40 m, which makes it a serious dive for experienced, suitably qualified divers, and it now holds rich marine life – wrasse, ling and the occasional seal. The season runs roughly April to October; book through a certified local operator who knows the site’s currents.
Kayaking & coastal exploration
Guided paddle tours are a quiet way to take in the fjord’s sheltered water. Eco Atlantic Adventures runs trips from Portsalon Pier to the Seven Arches sea caves, a stretch of coast only reachable from the water, with hidden beaches along the way. Summer kayak camps take younger paddlers (ages 8+), while more experienced ones can work the tidal channels around the islands. The currents through the narrows are strong, so check the tide tables before any of it.
Practical information
- Getting there – the lough is reached via the N13, with Buncrana, Rathmullan and Portsalon the main gateways. Bus Éireann links these towns to Derry and Letterkenny, and City of Derry Airport is about 30 km away. Car parking is available at most fort sites and coastal viewpoints.
- Best time to visit – winter (November–February) for the birds; late spring to early autumn (May–September) for the calmest water for kayaking and diving.
- Facilities – Fort Dunree has a visitor centre with maps and tour information. Blue Flag beaches like Ballymastocker Bay at Portsalon have parking, public toilets and picnic tables.
- Safety – the tidal currents can be strong, especially through the narrows and around the island channels. Stick to designated swimming areas, and carry proper safety gear for anything on the water.
- Accommodation – family B&Bs in Buncrana and self-catering cottages around Rathmullan, many with water views.
Nearby attractions
- Ballymastocker Bay – a Blue Flag strand of wide golden sand at Portsalon, good for a swim after a walk.
- Buncrana Shore Path – a coastal trail along the lough’s eastern edge, linking the town to quieter headland viewpoints.
- Grianán of Aileach – the stone ring fort on the hill above the southern shore, with views over both Lough Swilly and Lough Foyle.
- Fanad Head Lighthouse – at the tip of the Fanad peninsula, guarding the western side of the lough’s entrance.
For the best of it in a day, start at Fort Dunree for the museum and the view down the fjord, then drive round to Portsalon for the beach at Ballymastocker – and pack a waterproof whatever the forecast says.