A dramatic 25-metre sea arch — known locally as Na Bristí ("the trousers") — rising from the Atlantic off Donegal's wild Mullaghmullan Peninsula. One of Ireland's most photogenic coastal formations, rewarding those who make the short but rugged walk to its clifftop viewpoint.
A steep, narrow path leads down from the field to a boulder beach at the base of the arch. The final section is rope-assisted. You can then scramble over rocks to stand beneath the arch and see two smaller hidden arches nearby. Only attempt this at low tide — the beach floods completely when the tide comes in.
Crohy Head is a favourite among landscape photographers. Sunset transforms the arch with warm light, and including a person in the frame gives a striking sense of scale. Even moody, overcast conditions produce atmospheric black-and-white shots. Arranmore Island sits on the horizon to the northeast.
Just inland from the arch, fern-filled trenches mark the entrance to 19th-century soapstone (steatite) workings that operated until 1947. You can walk about 20 metres into one before reaching water. Ruined stone buildings from the mining era dot the surrounding fields.
A roughly 6.75 km loop takes in a Napoleonic signal tower (built 1804–06), a WWII Éire 74 navigational marker, a coast-watching lookout post, an old kelp house, and the impressive 1840s Famine Walls. Start from the GAA pitch near Crohy and follow the coastline south.
The main sea arch crashes into view from the grassy clifftop about 50 metres above the Atlantic. You can see the arch's full 'trouser-leg' shape — two rock legs with a gap between — while waves surge through below. No barriers, so keep back from the edge.
The Bristi Sea Stack offers several climbing routes ranging from Diff to HVS (4a–5b), first climbed in 2011. Access involves a 50-metre sea passage at low tide. The nearby Crohy Head sea cliffs also have numerous routes. This is serious adventure climbing — the Atlantic swell dictates whether it's climbable.
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