From the pier at Kilchoan head inland towards the centre of the village, turning left at the junction and then right after a further 500m. The road climbs gently out of the village and into an area of moorland below which are a complex of underground volcanic structures. These are the remains of a 55 million year old volcanic complex often known as the Ardnamurchan caldera. Its concentric rings can be seen from space (and in satellite photographs) although they are less obvious on the ground. The winding road undulates across this area until the junction a mile beyond the Sonachan Hotel where a left turn leads you to the lighthouse at Ardnamurchan Point itself, 8 miles from your start point.
There is a visitor centre and cafe and lighthouse itself is open from spring to autumn - and the view from the top justifies the effort both in cycling to the foot and in climbing the stairs!
The return to Kilchoan is by the outward route.