How Did The Giant's Causeway Form?

Nearly 60 million years in the making, the Giant’s Causeway is a geological marvel and a legendary story waiting to be explored.

Those iconic hexagonal basalt stones are the product of volcanic forces and cooling earth—but the folklore is just as captivating. Did a giant build the causeway for battle, or was it for love?

The Creation of the Giant’s Causeway

The Giant’s Causeway took shape around 60 million years ago when Ireland was still connected to North America. As Europe drifted away from North America, the earth’s crust cracked open, and molten lava surged through the fissures. The cooling lava formed layers of basalt rock.

Over time, rivers carved through these basalt layers were only filled once again by more lava flows. When the lower layers cooled slowly, they cracked into the neat, hexagonal shapes we see today. As glaciers scraped away the upper layers, rising sea levels and crashing waves helped to shape the landscape further, revealing the famous stone formations.

Key Stages in the Formation of the Causeway:

1. Volcanic eruptions layered molten basalt over a chalky landscape.
2. Erosion caused rivers to form through the basalt.
3. Lava flows filled the river valleys.
4. Slow cooling created the iconic hexagonal columns.
5. Glaciers and rising seas wore away the upper layers, exposing the stones.

Why Is It Called the Giant’s Causeway?

A Giant’s Feud, or a Love Story?

Legend has it that the Irish giant, Finn McCool, built the causeway to confront his Scottish rival, the giant Benandonner. When Finn saw how enormous Benandonner was, he fled back to Ireland. His wife cleverly disguised Finn as a baby, tricking Benandonner into believing the “father” of this giant child must be even bigger. Benandonner, terrified, ripped up the causeway as he fled back to Scotland.

However, there’s another version of the story—one that’s less about battle and more about love. An old poem discovered in a Norwegian library tells how Finn built the causeway to reach a Scottish maiden he had fallen in love with. In this tale, Finn’s grandmother, fearful of losing him to Scotland, summoned terrible storms to destroy the causeway each night as he tried to complete it.

Despite Finn’s perseverance, the storms repeatedly undid his work. On his final attempt, after battling fierce waves and lightning, he finally collapsed in the arms of his beloved on the Scottish shore. As the causeway slipped beneath the sea, his grandmother, stricken with grief at her actions, was turned to stone. Her figure is said to still stand on the coastline today, a silent witness to the legend.

Frozen in Time

If you visit the Giant’s Causeway, watch for traces of the myth. Finn McCool’s giant boot now turned to stone, can be found at Port Noffer. And if you look west from Port Ganny towards the Stookans headland, you might spot the stone figure of Finn’s grandmother, forever frozen in regret.

A World Heritage Site

In 1986, the Giant’s Causeway was designated a UNESCO World Heritage Site, recognised for its exceptional natural beauty and geological importance. Meeting two of UNESCO’s criteria, the Causeway is a place of both outstanding scenic value and a crucial chapter in the earth’s geological story.