8 August 2025 The Future is the Product of the Past

Archaeologists discovered a sunken prehistoric fort in Clew Bay island

A sunken prehistoric fort has been discovered on Clew Bay island off the north Mayo coast, Ireland.

It has been reported that the discovered fort may be as important as Dún Aonghasa, the largest of the prehistoric stone forts of the Aran Islands. It is located on Inis Mór, at the edge of a 100-meter-high (330-foot) cliff. Dún Aonghasa (unofficial anglicized version Dún Aengus), a popular tourist destination, is a significant archaeological site.

Archaeologist Michael Gibbons told the Irish Independent that initial surveys suggested that the island of Collanmore was a late Bronze Age fort.

The discovery of several large ramparts slicing through the tidal isthmus connecting the island to the shoreline outside of Westport provided the first clue.

One of the bigger islands in the bay, Collanmore, which is accessible by foot at very low tides, was once a base for the Glenans Irish Sailing Club.

The set of double ramparts are faced with large limestone blocks and extending for 200 to 300 meters, and are “most likely to be late Bronze Age in date, dating between 1100-900 BC”, Mr Gibbons said.

Both features are covered on high tide, and the site is “so large and coated in seaweed that one can see why it wasn’t discovered before”.

Walls of the sunken fort are revealed in low tide in Clew Bay. Photo: Irısh Independent
Walls of the sunken fort are revealed in low tide in Clew Bay. Photo: Irısh Independent

The archaeologist said they were lucky that day as there were men cutting seaweed in the same area. A team from Connemara and archaeologists from Mayo County Council were also present.

“This outer rampart — as in, the one nearest the mainland — was known to the locals, but they had no idea how old it was or how significant it is. Their size and scale “would suggest that the island was of major strategic importance at the time”.

Gibbons stated that similar ramparts can be seen in other coastal and lake promontory forts in the west of Ireland, with the closest examples being found to the north, including a large promontory fort defended by double ramparts north of Newport, Co Mayo, and a massive promontory fort on Lough Fee, located on the northern shores of Carra Lake.

“Late Bronze Age hillforts are the largest monuments built in Ireland and can measure up to 320 acres in area, with kilometers of defensive ramparts,” he said.

The later part of the Bronze Age (1500-700 BC) was a time of settlement expansion and economic prosperity in Ireland. Hillforts are another manifestation of a warrior culture that emerged not only in Ireland but across Europe during the Middle and Late Bronze Age.

“They were built by warlord-dominated societies and we have very good evidence they were in active use during periods of warfare between various tribes,” Gibson added.

The Clew Bay discovery has been reported to the National Monuments Service.

Cover Photo: Clew Bay, Co, Mayo, Wikipedia

Related Articles

Archaeologists reveal largest paleolithic cave art site in Eastern Iberia

17 September 2023

17 September 2023

More than 100 ancient paintings and engravings thought to be at least 24,000 years old were found in the cave...

A Special structure Contemporary to Göbeklitepe found at Gre Fılla Höyük in Eastern Turkey

4 August 2022

4 August 2022

Pit-bottomed structures dating to the Pre-Pottery Neolithic period were found at Gre Fılla Höyük (Gre Fılla Mound) in the province...

Ancient Tombs and 2-Meter Sarcophagus with Hieroglyphics Unearthed Near Aga Khan Mausoleum in Aswan

11 July 2025

11 July 2025

A joint Egyptian-Italian archaeological team has unearthed a significant collection of ancient rock-cut tombs near the Aga Khan Mausoleum on...

Unexpected Results Of Ancient DNA Study: Analysis sheds light on the early peopling of South America

3 November 2022

3 November 2022

Around 60,000 years ago, modern humans left Africa and quickly spread across six continents. Researchers can trace this epic migration...

A sculpture of a snake-bodied Roman-German deity was discovered in Stuttgart

23 April 2024

23 April 2024

A sculpture of a snake-bodied Roman-German deity was discovered at the Roman fort in Stuttgart, Germany. Since the beginning of...

The enigma behind King Tut’s’space dagger,’ according to archaeologists, has finally been solved

24 February 2022

24 February 2022

Archaeologists have finally solved the enigma of King Tutankhamun’s dagger, which was discovered 3,400 years ago. A new examination of...

Researchers Found Evidence in Ethiopia of a Human Population that Survived the Eruption of the Toba Supervolcano 74,000 Years Ago

22 March 2024

22 March 2024

Researchers working in the Horn of Africa, also known as the Somali Peninsula have uncovered evidence showing how Middle Stone...

Spanish Stonehenge re-emerges from the ‘Valdecañas reservoir’

19 August 2022

19 August 2022

Submerged by the Valdecañas reservoir for decades, the Guadalperal dolmen has been fully exposed as it was two summers ago....

The secret of the mummy in the Crystal coffin found in a garage in San Francisco

30 March 2023

30 March 2023

Mysterious mummies are a symbol of ancient lost times, which we often associate with Egypt and other ancient civilizations. Therefore,...

Will the Siloam Inscription be returned to Israel?

12 March 2022

12 March 2022

During the visit of Israeli President Isaac Herzog to Turkey, the claim that he wanted the Siloam Inscription, one of...

Unique Iron & Viking-Age Mortuary Houses Found in Norway

28 August 2024

28 August 2024

While building a road in the village of Vinjeøra in central Norway, three ancient mortuary houses dating back to the...

Forged 5,000 Years Ago: The World’s Oldest Swords Discovered at Arslantepe Mound, Türkiye

10 June 2025

10 June 2025

In the arid plains of Eastern Anatolia, nestled along the western bank of the Euphrates River near Malatya, Turkey, lies...

Archaeologists discover medieval a tableman gaming piece in Bedfordshire, England

26 April 2023

26 April 2023

Archaeologists in Bedfordshire, England, have made an intriguing discovery: a tableman gaming piece was discovered at a medieval site. Cotswold...

The excavations in ancient city of Aizanoi discovered the statue heads of Dionysus and Aphrodite

11 December 2023

11 December 2023

The heads of Aphrodite, the goddess of love and beauty, and Dionysus, the god of wine, were found in Aizanoi,...

Centuries-Old Shipwrecks in Costa Rica Identified as Danish Slave Ships

5 May 2025

5 May 2025

Marine archaeologists have definitively identified two long-known shipwrecks off the coast of Cahuita National Park in Costa Rica as the...