Dún Aonghasa

A fort on the edge of the world...

Atlantic Ocean waves repeatedly throw themselves against the cliffs, slowly wearing away at the island. Strong winds sculpt the long grass into smooth wisps. Thousands of stone slabs form a strong barrier around the cliffs. Come explore Dún Aonghasa on Inishmore.

The History of the Fort

A crescent of stone walls hugs the edge of Inishmore, one of the Aran Islands off the coast of western Ireland. The prehistoric fort is called Dún Aonghasa and is one of the best-preserved prehistoric forts in Ireland, according to Cillian de Grás, the manager of Dún Aonghasa. He said it was originally built around 1,100 B.C. in the late Bronze Age for Ireland.


“That’s a period where this part of Ireland was incredibly rich with lots and lots of metal work, lots of gold work, and lots of bronze weapons dating from this period,” de Grás said. “Several of these large forts were built around the country including this one here at Dún Aonghasa.”

A view of the cliffs at Dún Aonghasa.

De Grás said that the walls enclose 14 acres and is located strategically at the highest point on the island. Visitors can see both sides of the island while standing outside the walls. He also said that the fort had a great view of all the shipping traffic coming into Galway Bay from the ocean and that the merchants would have known about the "impressive" fort.


“They probably would’ve known these people on the island,” de Grás said.  He added that they sailed by the island with the premise that “‘These are organized people that are probably going to be looking for their cut of whatever we’re selling so we better give it to them.’”


The walls are made of dry stone that was quarried on site, according to de Grás. They can reach as high as 8 meters tall and 3 meters thick.


“The walls themselves are incredibly impressive and really are a testament to the skills of the builders that they’re standing over 3,000 years later,” de Grás said.

He said his favorite part of the monument is the chevel de fries, which is a band of jagged, upright rock that was built around the outer walls. They are meant to impede attackers from storming the walls.


“To get through it, it’s like picking your way through a thicket of stones,” de Grás said. “A horse wouldn’t be able to get through.”

These are some of the chevel de fries that border the fort.

The fort is extremely popular for tourists, according to de Grás. Many tourists travel to the island on a ferry from the west coast of Ireland. He said a high concentration of visitors come to the site from half an hour after the boat arrives to half an hour before the boat leaves, especially during June, July and August. This period of around six hours leads to heavy crowds on the cliffs.


During the busy months, he said they encourage tourists to visit other sites on the island to reduce the high volume of people coming to Dún Aonghasa. De Grás said the monument is run by the Office of Public Works, which is funded by taxpayers, so they don’t have to worry about attracting tourists.


“There are at least 10 other national monuments on this island that are not as famous or as iconic as Dún Aonghasa so we try and encourage people to visit those national monuments as well,” de Grás said. “Cuts down on wear and tear on the monument.”


Take a look at some of the other scenic areas on Inishmore. On a clear day, rent a bike near the ferry stop and bike to the different areas of the island.


Check out some of the other sites on the island. 

Top 3 Must Dos

View the cliffs

Check out the museum

Shop for wool

Getting There

Aran Island Ferries

1. Hop on the Aran Island Ferries bus near Eyre Square. It takes about 60 minutes to reach Ros a’ Mhíl, the village where the port is.

2. Catch a ride on the ferry to Inishmore. It takes about 40 minutes.

3. Once on Inishmore...

Rent a bike near the ferry port for about $11.50 (€10) and bike to the fort. It takes about 30 minutes.


Hop on a tour bus for about $17 (€15) that takes you to the fort. It takes about 15 minutes.

Pro tip: the bike allows you to see the island at a more leisurely pace while the bus takes you to see multiple sites that might be too far to bike to.

Dún Aonghasa Info

Address:  Kilmurvy, Co. Galway, Ireland

Website: www.aranislands.ie

Phone: +353 (99) 61008

Cost: Adults - $5.70 (€5)  Group/Senior - $4.56 (€4)  Child/Student - $3.42 (€5)  

Saints and Religion

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