Cliffs of Moher Facts

Dún Aonghasa, perched dramatically on a 300-foot cliff on the southern edge of Inis Mór, is a prehistoric marvel that transports visitors back in time. This semi-circular stone fort, enclosed by massive dry-stone walls, is thought to date back to 1500 BC, making it one of Europe’s most significant archaeological treasures.

One of the most striking and well-documented Cliffs of Moher facts is their height. At their highest point, the cliffs reach 214 metres, or 702 feet, above sea level. This point is located near O’Brien’s Tower, which stands close to the midpoint of the cliff line. From here, the cliffs drop almost vertically into the Atlantic Ocean below, creating one of the most dramatic coastal profiles in Ireland.

The cliffs extend for approximately 14 kilometres along the Atlantic coast, running from Hag’s Head in the south to an area near Doolin in the north. Their sheer height and length are the result of millions of years of geological processes, including sediment deposition and long-term erosion by the Atlantic Ocean. While many European coastlines feature high sea cliffs, the combination of elevation, scale, and uninterrupted ocean exposure makes the Cliffs of Moher particularly distinctive.

Despite their size, the cliffs are carefully managed to balance visitor access with safety and environmental protection. Designated pathways and viewing areas allow visitors to experience the height and scale of the cliffs while reducing erosion and risk. At the northern end near Doolin, there’s certainly no shortage of interesting Things to Do in Doolin, combining local culture with cliffside views.

The Cliffs of Moher were formed from layers of Namurian shale and sandstone, sedimentary rocks that were laid down approximately 320 million years ago during the Carboniferous period. At that time, this part of Ireland lay near the equator and was covered by a shallow tropical sea. Sediments carried by rivers settled on the seabed, gradually building up thick layers over millions of years.

Today, these layers are clearly visible in the cliff face. The harder sandstone forms more resistant bands, while the softer shale erodes more easily. This contrast plays a key role in shaping the stepped and vertical appearance of the cliffs. Ongoing erosion by wind, rain, and Atlantic waves continues to expose and reshape these rock layers, making the cliffs a constantly evolving landscape.

The cliffs form part of the Burren and Cliffs of Moher UNESCO Global Geopark, which recognises the international importance of the area’s geology. Visitors exploring the area often combine the Cliffs of Moher with nearby cultural sites such as Corcomroe Abbey, gaining both geological and historical insights.

O’Brien’s Tower is a stone observation tower located near the highest point of the Cliffs of Moher. It was built in 1835 by Cornelius O’Brien, a local landowner who later became a Member of Parliament. The tower was constructed to provide visitors with a viewing point over the cliffs and the Atlantic Ocean at a time when tourism to the area was beginning to grow.

From the top of the tower, weather and visibility permitting, visitors can see across the Atlantic towards the Aran Islands and Galway Bay. The surrounding islands are explored by many who take the Aran Islands & Cliffs of Moher tour for a combined experience. Today, O’Brien’s Tower remains one of the most recognisable landmarks along the cliff edge.

The Cliffs of Moher are a key highlight and Signature Discovery Point on the Wild Atlantic Way, a 2,500-kilometre coastal touring route along Ireland’s west coast. They are designated as a signature discovery point, representing one of the most distinctive and accessible experiences along the route. Visitors following the Wild Atlantic Way can reach the cliffs via several entry points, including Doolin, Liscannor, and through guided tours from Galway.

Many travellers extend their visit to other Galway Bay attractions, exploring more of the west coast’s dramatic coastline.

At the southern end of the cliffs lies Hag’s Head, named for a rock formation that resembles a woman’s head when viewed from the sea. This point forms a natural boundary for the cliffs and offers dramatic views of the ocean meeting the base of the cliffs. While steep and rugged, Hag’s Head is accessible by coastal pathways, providing insight into the geological continuity of the cliffs from south to north. The name “Moher” itself is derived from “Mothar,” an old Gaelic word for a ruined fort that once stood on this headland.

The Cliffs of Moher are part of a Special Protection Area (SPA) due to their importance for breeding seabirds. The cliffs host species such as Atlantic Puffins, razorbills, and guillemots, which nest on the ledges during the spring and summer months. This includes a significant Atlantic Puffin colony that is a major draw for wildlife enthusiasts. Conservation measures ensure that these birds can breed safely, and visitors are encouraged to remain on designated paths to avoid disturbing the wildlife.

The Cliffs face the full force of the Atlantic Ocean, which has played a key role in sculpting their vertical faces over thousands of years. At Aill na Searrach (Anglicised as Aileen’s Wave), a sea cave near the cliff base produces spectacular, sometimes explosive waves, making it a well-known feature for visitors. These natural forces continue to erode the cliffs slowly, demonstrating the ongoing interaction between rock, wind, and sea.

Nearby, Fanore Beach shows how the same geological and coastal processes shape the broader County Clare coastline.

The cliffs are associated with Irish legend, including The Legend of Mal and Cú Chulainn, in which the landscape features in heroic journeys and battles. While folklore, these tales remain an important part of the area’s cultural history. The cliffs have also captured the imagination of filmmakers and writers; they are said to have inspired the fictional “Cliffs of Insanity” in The Princess Bride.

Visitors can also see An Branán Mór (The Great Sea Stack), a striking rock formation standing just off the cliff edge. Such sea stacks are evidence of the Atlantic’s constant erosion and the layered geology of the cliffs.

The Cliffs of Moher combine stunning natural beauty, rich geological history, and cultural significance in a way few other places in Ireland do. From the dramatic vertical drop to the seabird colonies, O’Brien’s Tower, legends, and sea stacks, the cliffs offer more than just a scenic view. They are part of a UNESCO Global Geopark, a protected habitat, and a signature point on the Wild Atlantic Way, making them both a natural wonder and an important site for conservation and education.

Visitors gain a firsthand experience of Ireland’s rugged western coastline, the power of the Atlantic Ocean, and the layers of history embedded in the rocks. For practical guidance, this Cliffs of Moher visitor guide explains the best way to see the Cliffs of Moher in a single day. To plan your visit, explore the charming Towns Near the Cliffs of Moher for accommodation and local culture.