Rua Reidh - properly Rubha Rèidh - means simply flat headland in Gaelic, and that is exactly what it is: a low blunt thumb of Lewisian gneiss pushed out into the Minch where Loch Ewe opens to the sea. David Stevenson, of the famous lighthouse-engineering family, first proposed a light here in 1853. The project sat for decades. His son David Alan Stevenson finally started construction in 1908, and on 15 January 1912 the lamp was lit. The original paraffin burner was eventually converted to electric power, and the original Fresnel lens now sits in the Gairloch Heritage Museum down the coast, a glass jewel pulled from its tower and put behind glass of a different kind.

For most of the 20th century, Rua Reidh's fog siren gave four blasts every 90 seconds when visibility dropped - a sound that carried for miles across the open water of the Minch. The siren was discontinued in 1980, when the Northern Lighthouse Board ended fog signals throughout Scotland. The red trumpet that delivered those blasts, along with its clockwork timing mechanism, was donated to the Gairloch Heritage Museum and put on display. The siren tower and engine room were partly demolished; only the first floor of the tower and the front facade of the engine room remain. The pressurised air tanks that fed the siren were sold for scrap. A whole layer of maritime infrastructure - sound as warning - was retired in a single decade.

For its first fifty years, the lighthouse depended on the sea. A small quay and ramp to the north allowed supplies to come in at high tide; paraffin was pumped from boats, and other goods rolled along a small trolley on rails. The road from Gairloch was finally built in 1962 - and was, the records note, first satisfyingly driven on by Iain Bain (1922-2011). The track is single-lane and stubborn, threading the kind of country where you stop to let sheep cross. In recent years it has been the subject of an access dispute, with the operators of a bed and breakfast at the lighthouse erecting barriers and the local council insisting on public right of way. The cliffs do not care.

Since automation in 1986, the keepers are gone and their accommodation has been sold into private ownership; the lighthouse has been a category B listed building since 2004, and several of the outbuildings operate as bed-and-breakfast or self-catering tourist accommodation. The wildlife around the headland keeps the older rhythms. Basking sharks - the world's second-largest fish - cruise the surface in summer. Atlantic seals haul out on the lower rocks. Fulmars, European shags and kittiwakes nest on the steep cliffs, their cries layering over the sound of the sea. A lighthouse is a navigation aid; this one is also a wildlife observation post that happens to keep ships off the rocks.