The Stone a Giant Threw Across the Lough

High on the hillside above Rostrevor, where the land rises steeply from the shore of Carlingford Lough (Loch Cairlinn), a boulder the size of a small house sits on the open mountain. It is made of granite. It weighs approximately 50 tonnes. And it has no business being there.

According to the oldest stories, the stone was thrown across Carlingford Lough by Fionn Mac Cumhaill — the giant warrior of Irish mythology whose legends saturate every mountain and lake in this landscape. Fionn, so the story goes, was locked in a feud with a rival giant called Ruscaire, who lived on the hillside above Rostrevor. From his camp in the Cooley Mountains on the far shore, Fionn picked up a boulder, hurled it across the lough, and it landed here — 1,000 feet up the mountainside, where it has sat ever since.

Geologists have a different explanation, though it is no less dramatic. The Cloughmore Stone is what they call a glacial erratic — a rock transported far from its origin by the movement of ice sheets during the last glacial period, roughly 15,000 to 20,000 years ago. As the ice retreated, the boulder was deposited on the hillside, stranded in a place where it does not geologically belong. The granite of the stone does not match the rock beneath it. Something moved it here. The question is only whether it was ice or a giant.

Both stories share the same essential truth: something impossibly large was moved an impossible distance and left on a mountainside where it does not belong. The scientists explain it with ice sheets and millennia. The storytellers explain it with a giant and a grudge. Standing next to it, 1,000 feet above the lough, either version feels equally plausible.

The walk to the Cloch Mhór begins in Kilbroney Forest Park — a place that has its own stories. C.S. Lewis spent childhood holidays in Rostrevor and is said to have drawn inspiration from these woods for the landscapes of Narnia. The Narnia Trail through Kilbroney brings The Lion, The Witch and The Wardrobe to life with carved wooden sculptures among the ancient oaks.

From the main car park, a well-marked path climbs steadily through the forest. The trees thin as you gain height. After roughly 40 minutes, you emerge onto open hillside and there it is — a massive boulder, alone on the slope, with Carlingford Lough spread out below and the Cooley Mountains across the water. The sense of exposure is sudden and exhilarating. You have been in dense woodland for half an hour and now the whole lough opens up before you.